Sleep Calculator

About

😴 SLEEP CALCULATOR — Wake Up Refreshed Every Morning

Stop guessing when to go to bed. Sleep Calculator uses proven 90-minute sleep cycle science to show you exactly when to sleep or wake up — so you always rise between cycles, not in the middle of one.

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🛌 BEDTIME CALCULATOR
Enter when you need to wake up and get 3 ideal bedtime options — Best (6 cycles), Good (5 cycles), and Minimum (4 cycles). Includes the average 14-minute fall-asleep time for accurate results.

⏰ WAKE-UP CALCULATOR
Enter when you're going to sleep (or use your current time) and see the best wake-up times based on complete sleep cycles. Wake up naturally feeling rested, not groggy.

🎵 SLEEP SOUNDS (8 ambient sounds)
- 🌧️ Rain
- 🌊 Ocean Waves
- 📻 White Noise
- 🌲 Forest
- ⛈️ Thunder
- 💨 Wind
- 🔥 Fireplace
- 🏞️ River

All sounds are generated directly in your browser — no buffering, no ads, no internet required.

⏱️ SLEEP TIMER
Set sounds to automatically fade out after 15, 30, 45, 60, 90, or 120 minutes — or enter a custom duration. Perfect for falling asleep without leaving audio running all night.

🔔 ALARM
Set a wake-up alarm with your choice of ambient sound. Includes a 5-minute snooze button.

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✅ WHY SLEEP CALCULATOR?
- Based on real sleep cycle science (90-min NREM/REM cycles)
- 100% offline — sounds work without internet
- No ads, no subscriptions, no account needed
- No data collected — ever
- Lightweight and fast
- Manifest V3 — built to Chrome's latest security standard

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🔒 PRIVACY
This extension collects zero data. No tracking, no analytics, no network requests. Everything runs locally in your browser.

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Learn more at smartsleepcalc.com