DualUnits – Metric ⇄ Imperial

About

Never do unit math in your head again.

DualUnits automatically finds metric and imperial units on every website you visit and shows the converted value in a small, unobtrusive badge right next to the original – so you always see both, without clicking anything.

30°C becomes 30°C (86 °F). 65 mph becomes 65 mph (105 km/h). It just works, everywhere.

WHY INSTALL IT?

• Read foreign recipes, weather reports, sports news, product pages, and forums without stopping to convert units.
• Both values stay visible side by side – the original text is never replaced, so nothing is lost or distorted.
• Works on dynamic pages too: infinite scroll, live tickers, and single-page apps are converted the moment new content appears.

WHAT IT CONVERTS

• Temperature: °C ⇄ °F (including "degrees Celsius" / "Fahrenheit")
• Length & distance: km, m, cm, mm ⇄ miles, feet, inches, yards – even heights like 5'11"
• Weight: kg, g ⇄ pounds, ounces
• Volume: liters, ml ⇄ gallons, fl oz
• Speed: km/h ⇄ mph

It understands word forms ("kilometers", "pounds"), decimals, negative values, and thousands separators like 45,000 mm.

SMART DETECTION

DualUnits is careful about what it converts. It ignores money ($30), percentages (30%), model numbers (M4), abbreviations like 340M (million) or 5G, durations like "1h 25m" or "posted 25m ago", and timestamps on sites like X/Twitter, YouTube, and Reddit.

FULLY CONFIGURABLE

Click the toolbar icon to toggle the extension globally, disable it for individual sites, or switch categories (temperature, length, weight, volume, speed) on and off. Changes apply instantly to open tabs.

PRIVATE BY DESIGN

Everything runs locally in your browser. No data ever leaves your machine, no tracking, no accounts, no external servers. The only permission used is "storage" – to remember your settings.