Key Detector – Musical Key & BPM Finder

Tracking since Apr 1, 2026.

Changelog

• Jun 9, 2026
  description

  Detect the musical key & BPM of any audio in your browser. Transpose YouTube in real-time. Interactive piano keyboard included.
  
  🎵 KEY DETECTOR & TRANSPOSER — Musical Key Finder, BPM Detector & YouTube Pitch Transposer
  
  Instantly find the musical key and BPM of any song playing in your browser tab. No microphone needed — Key Detector analyzes your tab's audio directly, using professional-grade signal processing to identify key, mode, and tempo in seconds.
  
  Used by guitarists, singers, producers, music students, and transcribers to answer the #1 question: "What key is this song in?"
  
  
  ★ WHAT'S NEW IN v1.6.3
  
  • Clearer two-mode layout — DETECT (one-shot key + BPM result) and LIVE (continuous real-time detection). Simpler, more intuitive labels.
  • Your music keeps playing during analysis — we no longer mute the tab while detecting, and the analyzer now reads the full audio signal for more reliable results.
  • Bigger, clearer Tap BPM tool — tap along to the beat and read the tempo on a large, easy-to-see display.
  • Cleaner results — the detected key is the star, with streamlined alternative-key suggestions.
  • Refreshed piano highlighting — the detected key now stands out clearly from the rest of the scale.
  • Accessibility upgrades — full keyboard navigation for tabs, toggles, and the piano.
  • (Pro) Dark mode for late-night sessions.
  
  
  🔍 KEY DETECTION — DETECT MODE
  
  Analyzes 15–60 seconds of audio for maximum accuracy. Uses the Krumhansl-Schmuckler key-finding algorithm — the same method used in professional music analysis software — to detect all 24 major and minor keys.
  
  • Detects key and mode (major or minor) with confidence score
  • Color-coded confidence: green (high), amber (medium), red (low)
  • Shows top 3 alternative key candidates
  • BPM tempo detection included
  • Manual Tap BPM tool — tap along to find the tempo by hand
  • Results saved to session history
  
  
  🎹 INTERACTIVE PIANO KEYBOARD
  
  • C4–C5 range with accurate black and white key layout
  • Highlights root note and in-scale tones for any key
  • Manual root selector (C, C♯, D, D♯, E, F, F♯, G, G♯, A, A♯, B)
  • Scale selector: Chromatic, Major, Minor
  • Click any key to hear the note (built-in audio synthesis)
  • Auto-syncs with Detect results — no manual input needed
  
  
  ⚡ LIVE KEY DETECTION
  
  Continuous detection mode that updates every few seconds as the audio plays. Great for tracking modulations in longer tracks or getting a quick read before committing to a full Detect analysis.
  
  
  🎛️ STUDIO MODE — PITCH TRANSPOSER (Pro)
  
  Transpose YouTube videos up or down by any number of semitones — in real-time, without affecting playback speed. Powered by SoundTouch audio processing. Ideal for:
  • Singers who want to perform a song in a more comfortable key
  • Guitarists who want to play along without retuning
  • Producers matching the key of a sample to their project
  
  
  📋 SESSION HISTORY
  
  Every key and BPM detection is logged automatically. Review your recent analyses, compare results across songs, and pick up where you left off.
  
  
  WHO IS KEY DETECTOR FOR?
  
  ✓ Guitarists & instrumentalists — find the key of any song to jam along
  ✓ Singers & vocalists — detect key before performing, transpose to your range with Studio Mode
  ✓ Music producers & DJs — confirm key and BPM for harmonic mixing and mashups
  ✓ Music students — visualize scales on the piano keyboard, practice ear training
  ✓ Transcribers & arrangers — identify key signatures in seconds, not minutes
  ✓ Karaoke singers — transpose YouTube songs to match your voice
  ✓ Songwriters — quickly identify the key of a reference track
  
  
  HOW IT WORKS (Technical)
  
  Key Detector uses the Web Audio API to capture your tab's audio stream in real time. The Krumhansl-Schmuckler algorithm computes pitch class profiles across the audio and correlates them against all 24 major/minor key templates to find the best match. BPM is detected via spectral flux analysis. The interactive piano uses Web Audio oscillator synthesis for note playback. Everything runs locally in your browser.
  
  
  🔒 PRIVACY — 100% LOCAL PROCESSING
  
  Your audio never leaves your device. Key Detector processes everything directly in the browser — no audio is uploaded, recorded, or stored on any server. Detection only runs when you actively start it. We collect no personal data.
  
  
  FREE vs PRO
  
  Free:
  • Key detection (Detect mode)
  • BPM detection + manual Tap BPM tool
  • Live (real-time) detection mode
  • Interactive piano keyboard (C4–C5, root + scale selector)
  • Session history (last 5 results)
  
  Pro (one-time purchase):
  • Studio Mode — real-time pitch transposer for YouTube
  • Camelot wheel — DJ & harmonic-mixing notation
  • Dark mode
  • Extended session history
  • Early access to new features
  
  
  SUPPORTED SITES
  
  Works on YouTube, SoundCloud, Spotify Web, Bandcamp, and virtually any website that plays audio in a browser tab.
  
  
  If Key Detector helped you find the key of a song you've been searching for, please take a moment to leave a review — it helps other musicians discover this tool. 🎵

  🎵 KEY DETECTOR & TRANSPOSER — Musical Key Finder, BPM Detector & YouTube Pitch Transposer
  
  Instantly find the musical key and BPM of any song playing in your browser tab. No microphone needed — Key Detector analyzes your tab's audio directly, using professional-grade signal processing to identify key, mode, and tempo in seconds.
  
  Used by guitarists, singers, producers, music students, and transcribers to answer the #1 question: "What key is this song in?"
  
  
  ★ WHAT'S NEW IN v1.6.3
  
  • Clearer two-mode layout — DETECT (one-shot key + BPM result) and LIVE (continuous real-time detection). Simpler, more intuitive labels.
  • Your music keeps playing during analysis — we no longer mute the tab while detecting, and the analyzer now reads the full audio signal for more reliable results.
  • Bigger, clearer Tap BPM tool — tap along to the beat and read the tempo on a large, easy-to-see display.
  • Cleaner results — the detected key is the star, with streamlined alternative-key suggestions.
  • Refreshed piano highlighting — the detected key now stands out clearly from the rest of the scale.
  • Accessibility upgrades — full keyboard navigation for tabs, toggles, and the piano.
  • (Pro) Dark mode for late-night sessions.
  
  
  🔍 KEY DETECTION — DETECT MODE
  
  Analyzes 15–60 seconds of audio for maximum accuracy. Uses the Krumhansl-Schmuckler key-finding algorithm — the same method used in professional music analysis software — to detect all 24 major and minor keys.
  
  • Detects key and mode (major or minor) with confidence score
  • Color-coded confidence: green (high), amber (medium), red (low)
  • Shows top 3 alternative key candidates
  • BPM tempo detection included
  • Manual Tap BPM tool — tap along to find the tempo by hand
  • Results saved to session history
  
  
  🎹 INTERACTIVE PIANO KEYBOARD
  
  • C4–C5 range with accurate black and white key layout
  • Highlights root note and in-scale tones for any key
  • Manual root selector (C, C♯, D, D♯, E, F, F♯, G, G♯, A, A♯, B)
  • Scale selector: Chromatic, Major, Minor
  • Click any key to hear the note (built-in audio synthesis)
  • Auto-syncs with Detect results — no manual input needed
  
  
  ⚡ LIVE KEY DETECTION
  
  Continuous detection mode that updates every few seconds as the audio plays. Great for tracking modulations in longer tracks or getting a quick read before committing to a full Detect analysis.
  
  
  🎛️ STUDIO MODE — PITCH TRANSPOSER (Pro)
  
  Transpose YouTube videos up or down by any number of semitones — in real-time, without affecting playback speed. Powered by SoundTouch audio processing. Ideal for:
  • Singers who want to perform a song in a more comfortable key
  • Guitarists who want to play along without retuning
  • Producers matching the key of a sample to their project
  
  
  📋 SESSION HISTORY
  
  Every key and BPM detection is logged automatically. Review your recent analyses, compare results across songs, and pick up where you left off.
  
  
  WHO IS KEY DETECTOR FOR?
  
  ✓ Guitarists & instrumentalists — find the key of any song to jam along
  ✓ Singers & vocalists — detect key before performing, transpose to your range with Studio Mode
  ✓ Music producers & DJs — confirm key and BPM for harmonic mixing and mashups
  ✓ Music students — visualize scales on the piano keyboard, practice ear training
  ✓ Transcribers & arrangers — identify key signatures in seconds, not minutes
  ✓ Karaoke singers — transpose YouTube songs to match your voice
  ✓ Songwriters — quickly identify the key of a reference track
  
  
  HOW IT WORKS (Technical)
  
  Key Detector uses the Web Audio API to capture your tab's audio stream in real time. The Krumhansl-Schmuckler algorithm computes pitch class profiles across the audio and correlates them against all 24 major/minor key templates to find the best match. BPM is detected via spectral flux analysis. The interactive piano uses Web Audio oscillator synthesis for note playback. Everything runs locally in your browser.
  
  
  🔒 PRIVACY — 100% LOCAL PROCESSING
  
  Your audio never leaves your device. Key Detector processes everything directly in the browser — no audio is uploaded, recorded, or stored on any server. Detection only runs when you actively start it. We collect no personal data.
  
  
  FREE vs PRO
  
  Free:
  • Key detection (Detect mode)
  • BPM detection + manual Tap BPM tool
  • Live (real-time) detection mode
  • Interactive piano keyboard (C4–C5, root + scale selector)
  • Session history (last 5 results)
  
  Pro (one-time purchase):
  • Studio Mode — real-time pitch transposer for YouTube
  • Camelot wheel — DJ & harmonic-mixing notation
  • Dark mode
  • Extended session history
  • Early access to new features
  
  
  SUPPORTED SITES
  
  Works on YouTube, SoundCloud, Spotify Web, Bandcamp, and virtually any website that plays audio in a browser tab.
  
  
  If Key Detector helped you find the key of a song you've been searching for, please take a moment to leave a review — it helps other musicians discover this tool. 🎵

• Jun 3, 2026
  description

  🎵 KEY DETECTOR & TRANSPOSER — Musical Key Finder, BPM Detector & YouTube Pitch Transposer
  
  Instantly find the musical key and BPM of any song playing in your browser tab. No microphone needed — Key Detector analyzes your tab's audio directly, using professional-grade signal processing to identify key, mode, and tempo in seconds.
  
  Used by guitarists, singers, producers, music students, and transcribers to answer the #1 question: "What key is this song in?"
  
  
  ★ WHAT'S NEW IN v1.5 — Interactive Piano Keyboard
  
  The most-requested feature is here: a full C4–C5 interactive piano keyboard built right into the extension. Select any root note (C through B) and scale type (Chromatic, Major, or Minor) — the keyboard highlights which notes belong to that scale. When you run a key detection, the piano auto-syncs to the detected key and mode, so you can immediately see and hear the scale you're working with. Perfect for music theory practice, ear training, and finding the right notes to play along.
  
  
  🔍 KEY DETECTION — VERDICT MODE
  
  Analyzes 15–60 seconds of audio for maximum accuracy. Uses the Krumhansl-Schmuckler key-finding algorithm — the same method used in professional music analysis software — to detect all 24 major and minor keys.
  
  • Detects key and mode (major or minor) with confidence score
  • Color-coded confidence: green (high), amber (medium), red (low)
  • Shows top 3 alternative key candidates with probability percentages
  • BPM tempo detection included
  • Results saved to session history
  
  
  🎹 INTERACTIVE PIANO KEYBOARD (NEW in v1.5)
  
  • C4–C5 range with accurate black and white key layout
  • Highlights root note and in-scale tones for any key
  • Manual root selector (C, C♯, D, D♯, E, F, F♯, G, G♯, A, A♯, B)
  • Scale selector: Chromatic, Major, Minor
  • Click any key to hear the note (built-in audio synthesis)
  • Auto-syncs with Verdict results — no manual input needed
  
  
  ⚡ REAL-TIME KEY DETECTION
  
  Continuous detection mode that updates every few seconds as the audio plays. Great for tracking modulations in longer tracks or getting a quick read before committing to a full Verdict analysis.
  
  
  🎛️ STUDIO MODE — PITCH TRANSPOSER (Pro)
  
  Transpose YouTube videos up or down by any number of semitones — in real-time, without affecting playback speed. Powered by SoundTouch audio processing. Ideal for:
  • Singers who want to perform a song in a more comfortable key
  • Guitarists who want to play along without retuning
  • Producers matching the key of a sample to their project
  
  
  📋 SESSION HISTORY
  
  Every key and BPM detection is logged automatically. Review your recent analyses, compare results across songs, and pick up where you left off.
  
  
  WHO IS KEY DETECTOR FOR?
  
  ✓ Guitarists & instrumentalists — find the key of any song to jam along
  ✓ Singers & vocalists — detect key before performing, transpose to your range with Studio Mode
  ✓ Music producers & DJs — confirm key and BPM for harmonic mixing and mashups
  ✓ Music students — visualize scales on the piano keyboard, practice ear training
  ✓ Transcribers & arrangers — identify key signatures in seconds, not minutes
  ✓ Karaoke singers — transpose YouTube songs to match your voice
  ✓ Songwriters — quickly identify the key of a reference track
  
  
  HOW IT WORKS (Technical)
  
  Key Detector uses the Web Audio API to capture your tab's audio stream in real time. The Krumhansl-Schmuckler algorithm computes pitch class profiles across the audio and correlates them against all 24 major/minor key templates to find the best match. BPM is detected via spectral flux analysis. The interactive piano uses Web Audio oscillator synthesis for note playback. Everything runs locally in your browser.
  
  
  🔒 PRIVACY — 100% LOCAL PROCESSING
  
  Your audio never leaves your device. Key Detector processes everything directly in the browser — no audio is uploaded, recorded, or stored on any server. Detection only runs when you actively click Start. We collect no personal data.
  
  
  FREE vs PRO
  
  Free:
  • Key detection (Verdict Mode)
  • BPM detection
  • Real-time detection mode
  • Interactive piano keyboard (C4–C5, root + scale selector)
  • Session history (last 5 results)
  
  Pro (one-time purchase):
  • Studio Mode — real-time pitch transposer for YouTube
  • Extended session history
  • Early access to new features
  
  
  SUPPORTED SITES
  
  Works on YouTube, SoundCloud, Spotify Web, Bandcamp, and virtually any website that plays audio in a browser tab.
  
  
  If Key Detector helped you find the key of a song you've been searching for, please take a moment to leave a review — it helps other musicians discover this tool. 🎵

  Detect the musical key & BPM of any audio in your browser. Transpose YouTube in real-time. Interactive piano keyboard included.
  
  🎵 KEY DETECTOR & TRANSPOSER — Musical Key Finder, BPM Detector & YouTube Pitch Transposer
  
  Instantly find the musical key and BPM of any song playing in your browser tab. No microphone needed — Key Detector analyzes your tab's audio directly, using professional-grade signal processing to identify key, mode, and tempo in seconds.
  
  Used by guitarists, singers, producers, music students, and transcribers to answer the #1 question: "What key is this song in?"
  
  
  ★ WHAT'S NEW IN v1.6.3
  
  • Clearer two-mode layout — DETECT (one-shot key + BPM result) and LIVE (continuous real-time detection). Simpler, more intuitive labels.
  • Your music keeps playing during analysis — we no longer mute the tab while detecting, and the analyzer now reads the full audio signal for more reliable results.
  • Bigger, clearer Tap BPM tool — tap along to the beat and read the tempo on a large, easy-to-see display.
  • Cleaner results — the detected key is the star, with streamlined alternative-key suggestions.
  • Refreshed piano highlighting — the detected key now stands out clearly from the rest of the scale.
  • Accessibility upgrades — full keyboard navigation for tabs, toggles, and the piano.
  • (Pro) Dark mode for late-night sessions.
  
  
  🔍 KEY DETECTION — DETECT MODE
  
  Analyzes 15–60 seconds of audio for maximum accuracy. Uses the Krumhansl-Schmuckler key-finding algorithm — the same method used in professional music analysis software — to detect all 24 major and minor keys.
  
  • Detects key and mode (major or minor) with confidence score
  • Color-coded confidence: green (high), amber (medium), red (low)
  • Shows top 3 alternative key candidates
  • BPM tempo detection included
  • Manual Tap BPM tool — tap along to find the tempo by hand
  • Results saved to session history
  
  
  🎹 INTERACTIVE PIANO KEYBOARD
  
  • C4–C5 range with accurate black and white key layout
  • Highlights root note and in-scale tones for any key
  • Manual root selector (C, C♯, D, D♯, E, F, F♯, G, G♯, A, A♯, B)
  • Scale selector: Chromatic, Major, Minor
  • Click any key to hear the note (built-in audio synthesis)
  • Auto-syncs with Detect results — no manual input needed
  
  
  ⚡ LIVE KEY DETECTION
  
  Continuous detection mode that updates every few seconds as the audio plays. Great for tracking modulations in longer tracks or getting a quick read before committing to a full Detect analysis.
  
  
  🎛️ STUDIO MODE — PITCH TRANSPOSER (Pro)
  
  Transpose YouTube videos up or down by any number of semitones — in real-time, without affecting playback speed. Powered by SoundTouch audio processing. Ideal for:
  • Singers who want to perform a song in a more comfortable key
  • Guitarists who want to play along without retuning
  • Producers matching the key of a sample to their project
  
  
  📋 SESSION HISTORY
  
  Every key and BPM detection is logged automatically. Review your recent analyses, compare results across songs, and pick up where you left off.
  
  
  WHO IS KEY DETECTOR FOR?
  
  ✓ Guitarists & instrumentalists — find the key of any song to jam along
  ✓ Singers & vocalists — detect key before performing, transpose to your range with Studio Mode
  ✓ Music producers & DJs — confirm key and BPM for harmonic mixing and mashups
  ✓ Music students — visualize scales on the piano keyboard, practice ear training
  ✓ Transcribers & arrangers — identify key signatures in seconds, not minutes
  ✓ Karaoke singers — transpose YouTube songs to match your voice
  ✓ Songwriters — quickly identify the key of a reference track
  
  
  HOW IT WORKS (Technical)
  
  Key Detector uses the Web Audio API to capture your tab's audio stream in real time. The Krumhansl-Schmuckler algorithm computes pitch class profiles across the audio and correlates them against all 24 major/minor key templates to find the best match. BPM is detected via spectral flux analysis. The interactive piano uses Web Audio oscillator synthesis for note playback. Everything runs locally in your browser.
  
  
  🔒 PRIVACY — 100% LOCAL PROCESSING
  
  Your audio never leaves your device. Key Detector processes everything directly in the browser — no audio is uploaded, recorded, or stored on any server. Detection only runs when you actively start it. We collect no personal data.
  
  
  FREE vs PRO
  
  Free:
  • Key detection (Detect mode)
  • BPM detection + manual Tap BPM tool
  • Live (real-time) detection mode
  • Interactive piano keyboard (C4–C5, root + scale selector)
  • Session history (last 5 results)
  
  Pro (one-time purchase):
  • Studio Mode — real-time pitch transposer for YouTube
  • Camelot wheel — DJ & harmonic-mixing notation
  • Dark mode
  • Extended session history
  • Early access to new features
  
  
  SUPPORTED SITES
  
  Works on YouTube, SoundCloud, Spotify Web, Bandcamp, and virtually any website that plays audio in a browser tab.
  
  
  If Key Detector helped you find the key of a song you've been searching for, please take a moment to leave a review — it helps other musicians discover this tool. 🎵

• May 27, 2026
  description

  Instantly identify the musical key and tempo of any audio playing in your browser — YouTube, Spotify, SoundCloud, or any other site. Key Detector uses professional-grade audio analysis to give musicians, DJs, worship leaders, and producers accurate, actionable results in seconds.
  
  ── HOW IT WORKS ──
  
  Key Detector captures your tab's audio and runs it through the Krumhansl-Schmuckler key-finding algorithm with a chromagram (pitch-class energy analysis). All processing happens 100% locally in your browser. No audio is ever recorded, uploaded, or transmitted.
  
  ── CORE FEATURES ──
  
  🏆 Verdict Mode
  Accumulates audio over a configurable window for maximum accuracy. Choose 15s or 30s (free), or 45s / 60s (Pro). The result includes the detected key, mode (Major/Minor), a confidence score, tempo in BPM, and the top alternative keys so you can make an informed decision.
  
  ⚡ Real-Time Mode
  Watch the key and BPM update live as the song plays. The chromagram ring visualizes pitch-class energy in real time — great for modulating tracks or songs with multiple key sections.
  
  🎛️ Studio Mode — Speed & Transpose (YouTube)
  Control playback speed (0.25× to 2×) without changing pitch. Pro users can also transpose the pitch of any YouTube video in real-time by up to ±12 semitones using SoundTouch audio processing — perfect for learning songs in a different key or adapting worship music to your vocal range.
  
  📜 Session History
  Every result is saved automatically so you can compare keys across songs. Pro users get unlimited history; free users get the last 5 results.
  
  ── DISPLAY OPTIONS ──
  
  • ♯ Sharps or ♭ Flats notation
  • 8B Camelot Wheel notation for DJ harmonic mixing (Pro)
  • Toggle BPM visibility on or off
  • Set your default tab on open (Verdict / Real-time / Studio)
  
  ── PRO FEATURES ──
  
  Upgrade once, use on every Chrome you sign into. Pro unlocks:
  ✓ Real-time Transpose — change the key of any YouTube song
  ✓ 45s & 60s Verdict windows — maximum precision for complex songs
  ✓ Camelot Wheel notation — standard DJ harmonic mixing system
  ✓ Unlimited session history
  ✓ Side Panel mode — persistent wide panel that stays open while you browse
  ✓ Cross-device license — log in with your email to restore on any computer
  
  ── PRIVACY ──
  
  All audio analysis is performed locally using the Web Audio API. Key Detector never records, stores, or transmits your audio. The extension only requests the permissions it actually needs.
  
  ── PERFECT FOR ──
  
  - Musicians learning songs by ear
  - Worship leaders transposing songs to fit vocal ranges
  - DJs building harmonically compatible playlists
  - Producers identifying the key of samples and loops
  - Music students developing relative pitch and theory skills
  - Anyone who wants to know what key a song is in — instantly
  
  Stop guessing. Open Key Detector, press Start, and know the key in seconds.

  🎵 KEY DETECTOR & TRANSPOSER — Musical Key Finder, BPM Detector & YouTube Pitch Transposer
  
  Instantly find the musical key and BPM of any song playing in your browser tab. No microphone needed — Key Detector analyzes your tab's audio directly, using professional-grade signal processing to identify key, mode, and tempo in seconds.
  
  Used by guitarists, singers, producers, music students, and transcribers to answer the #1 question: "What key is this song in?"
  
  
  ★ WHAT'S NEW IN v1.5 — Interactive Piano Keyboard
  
  The most-requested feature is here: a full C4–C5 interactive piano keyboard built right into the extension. Select any root note (C through B) and scale type (Chromatic, Major, or Minor) — the keyboard highlights which notes belong to that scale. When you run a key detection, the piano auto-syncs to the detected key and mode, so you can immediately see and hear the scale you're working with. Perfect for music theory practice, ear training, and finding the right notes to play along.
  
  
  🔍 KEY DETECTION — VERDICT MODE
  
  Analyzes 15–60 seconds of audio for maximum accuracy. Uses the Krumhansl-Schmuckler key-finding algorithm — the same method used in professional music analysis software — to detect all 24 major and minor keys.
  
  • Detects key and mode (major or minor) with confidence score
  • Color-coded confidence: green (high), amber (medium), red (low)
  • Shows top 3 alternative key candidates with probability percentages
  • BPM tempo detection included
  • Results saved to session history
  
  
  🎹 INTERACTIVE PIANO KEYBOARD (NEW in v1.5)
  
  • C4–C5 range with accurate black and white key layout
  • Highlights root note and in-scale tones for any key
  • Manual root selector (C, C♯, D, D♯, E, F, F♯, G, G♯, A, A♯, B)
  • Scale selector: Chromatic, Major, Minor
  • Click any key to hear the note (built-in audio synthesis)
  • Auto-syncs with Verdict results — no manual input needed
  
  
  ⚡ REAL-TIME KEY DETECTION
  
  Continuous detection mode that updates every few seconds as the audio plays. Great for tracking modulations in longer tracks or getting a quick read before committing to a full Verdict analysis.
  
  
  🎛️ STUDIO MODE — PITCH TRANSPOSER (Pro)
  
  Transpose YouTube videos up or down by any number of semitones — in real-time, without affecting playback speed. Powered by SoundTouch audio processing. Ideal for:
  • Singers who want to perform a song in a more comfortable key
  • Guitarists who want to play along without retuning
  • Producers matching the key of a sample to their project
  
  
  📋 SESSION HISTORY
  
  Every key and BPM detection is logged automatically. Review your recent analyses, compare results across songs, and pick up where you left off.
  
  
  WHO IS KEY DETECTOR FOR?
  
  ✓ Guitarists & instrumentalists — find the key of any song to jam along
  ✓ Singers & vocalists — detect key before performing, transpose to your range with Studio Mode
  ✓ Music producers & DJs — confirm key and BPM for harmonic mixing and mashups
  ✓ Music students — visualize scales on the piano keyboard, practice ear training
  ✓ Transcribers & arrangers — identify key signatures in seconds, not minutes
  ✓ Karaoke singers — transpose YouTube songs to match your voice
  ✓ Songwriters — quickly identify the key of a reference track
  
  
  HOW IT WORKS (Technical)
  
  Key Detector uses the Web Audio API to capture your tab's audio stream in real time. The Krumhansl-Schmuckler algorithm computes pitch class profiles across the audio and correlates them against all 24 major/minor key templates to find the best match. BPM is detected via spectral flux analysis. The interactive piano uses Web Audio oscillator synthesis for note playback. Everything runs locally in your browser.
  
  
  🔒 PRIVACY — 100% LOCAL PROCESSING
  
  Your audio never leaves your device. Key Detector processes everything directly in the browser — no audio is uploaded, recorded, or stored on any server. Detection only runs when you actively click Start. We collect no personal data.
  
  
  FREE vs PRO
  
  Free:
  • Key detection (Verdict Mode)
  • BPM detection
  • Real-time detection mode
  • Interactive piano keyboard (C4–C5, root + scale selector)
  • Session history (last 5 results)
  
  Pro (one-time purchase):
  • Studio Mode — real-time pitch transposer for YouTube
  • Extended session history
  • Early access to new features
  
  
  SUPPORTED SITES
  
  Works on YouTube, SoundCloud, Spotify Web, Bandcamp, and virtually any website that plays audio in a browser tab.
  
  
  If Key Detector helped you find the key of a song you've been searching for, please take a moment to leave a review — it helps other musicians discover this tool. 🎵

• May 27, 2026
  short_description

  Detect the musical key & BPM of any audio in your tab, then transpose songs in real-time on YouTube. Built for musicians.

  Detect the musical key & BPM of any audio in your browser. Transpose YouTube in real-time. Interactive piano keyboard included.

• May 27, 2026
  name

  🎵 Key Detector & Transposer

  Key Detector – Musical Key & BPM Finder

• May 10, 2026
  description

  Instantly identify the musical key of any audio playing in your browser. Whether you're on YouTube, Spotify, SoundCloud, or any other site, Key Detector provides accurate, professional-grade audio analysis for musicians, DJs, and music students.
  
  Using advanced Web Audio API processing and the Krumhansl-Schmuckler key-finding algorithm, this extension listens to your active tab and extracts pitch data to give you the most reliable results possible.
  
  Core Features:
  
  🏆 Verdict Mode: Get a definitive key result with a color-coded confidence score. Choose between 15, 30, 45, or 60-second analysis windows for maximum accuracy.
  
  ⚡ Live Analysis: Perfect for modulating tracks. Watch a real-time chromagram ring and confidence bar as the song progresses.
  
  🔒 Intelligent Key Lock: Once a high-confidence key is detected, the extension can lock the result so you can focus on your instrument.
  
  Privacy-First Design: All audio analysis is performed 100% locally in your browser. We never record, save, or transmit your audio data.
  
  Perfect for:
  
  - Musicians: Learn songs by ear faster by knowing the exact key.
  
  - DJs: Find the key of tracks for perfect harmonic mixing.
  
  - Producers: Identify the key of samples and loops on the fly.
  
  - Students: Improve your relative pitch and music theory understanding.
  
  Stop guessing the key and start playing. Install Key Detector today!

  Instantly identify the musical key and tempo of any audio playing in your browser — YouTube, Spotify, SoundCloud, or any other site. Key Detector uses professional-grade audio analysis to give musicians, DJs, worship leaders, and producers accurate, actionable results in seconds.
  
  ── HOW IT WORKS ──
  
  Key Detector captures your tab's audio and runs it through the Krumhansl-Schmuckler key-finding algorithm with a chromagram (pitch-class energy analysis). All processing happens 100% locally in your browser. No audio is ever recorded, uploaded, or transmitted.
  
  ── CORE FEATURES ──
  
  🏆 Verdict Mode
  Accumulates audio over a configurable window for maximum accuracy. Choose 15s or 30s (free), or 45s / 60s (Pro). The result includes the detected key, mode (Major/Minor), a confidence score, tempo in BPM, and the top alternative keys so you can make an informed decision.
  
  ⚡ Real-Time Mode
  Watch the key and BPM update live as the song plays. The chromagram ring visualizes pitch-class energy in real time — great for modulating tracks or songs with multiple key sections.
  
  🎛️ Studio Mode — Speed & Transpose (YouTube)
  Control playback speed (0.25× to 2×) without changing pitch. Pro users can also transpose the pitch of any YouTube video in real-time by up to ±12 semitones using SoundTouch audio processing — perfect for learning songs in a different key or adapting worship music to your vocal range.
  
  📜 Session History
  Every result is saved automatically so you can compare keys across songs. Pro users get unlimited history; free users get the last 5 results.
  
  ── DISPLAY OPTIONS ──
  
  • ♯ Sharps or ♭ Flats notation
  • 8B Camelot Wheel notation for DJ harmonic mixing (Pro)
  • Toggle BPM visibility on or off
  • Set your default tab on open (Verdict / Real-time / Studio)
  
  ── PRO FEATURES ──
  
  Upgrade once, use on every Chrome you sign into. Pro unlocks:
  ✓ Real-time Transpose — change the key of any YouTube song
  ✓ 45s & 60s Verdict windows — maximum precision for complex songs
  ✓ Camelot Wheel notation — standard DJ harmonic mixing system
  ✓ Unlimited session history
  ✓ Side Panel mode — persistent wide panel that stays open while you browse
  ✓ Cross-device license — log in with your email to restore on any computer
  
  ── PRIVACY ──
  
  All audio analysis is performed locally using the Web Audio API. Key Detector never records, stores, or transmits your audio. The extension only requests the permissions it actually needs.
  
  ── PERFECT FOR ──
  
  - Musicians learning songs by ear
  - Worship leaders transposing songs to fit vocal ranges
  - DJs building harmonically compatible playlists
  - Producers identifying the key of samples and loops
  - Music students developing relative pitch and theory skills
  - Anyone who wants to know what key a song is in — instantly
  
  Stop guessing. Open Key Detector, press Start, and know the key in seconds.

• May 10, 2026
  short_description

  Instantly identify the musical key of any audio playing in your tab (YouTube, Spotify, etc.)

  Detect the musical key & BPM of any audio in your tab, then transpose songs in real-time on YouTube. Built for musicians.

• May 10, 2026
  name

  🎵 Key Detector - Real-time Song Key Finder

  🎵 Key Detector & Transposer

• May 10, 2026
  host_permissions

  (empty)

  *://*.youtube.com/*, *://*.youtu.be/*, https://extensionpay.com/*

• May 10, 2026
  permissions

  tabCapture, activeTab

  tabCapture, activeTab, storage, sidePanel, scripting

Permissions & access

Permissions

tabCaptureactiveTabstoragesidePanelscripting

Host access

*://*.youtube.com/*, *://*.youtu.be/*, https://extensionpay.com/*

Screenshots

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