Metric ⇄ Imperial Unit Converter
Convert length, weight, volume, and temperature between metric and imperial units instantly. Runs entirely in your browser. Nothing you type is ever uploaded.
What can you convert?
UnitFlip switches between metric and imperial (and US customary) units across four everyday categories: length (millimeters through miles), weight (grams through stone), volume (milliliters through gallons), and temperature (Celsius, Fahrenheit, Kelvin). Pick a category, enter a value, and choose the units on either side. The result updates as you type.
Want to know how a unit mix-up destroyed a $125M spacecraft? Read Costly Unit-Conversion Mix-Ups.
How it works
Every conversion runs directly in your browser using standard, internationally-defined conversion factors. Nothing is sent to a server, so it works even offline once the page has loaded. Use the swap button to flip the from/to units without retyping your value.
Frequently asked questions
Is this free to use?
Yes. There's no sign-up and no limit on how many conversions you run.
Do you store what I type?
No. Every conversion happens entirely client-side in your browser. See the privacy policy for details.
How accurate are the conversions?
Conversions use standard internationally-defined conversion factors (for example, 1 inch = 2.54 cm exactly) and are precise to 6 significant figures.
Which units are supported?
Length, weight/mass, volume, and temperature, covering the most common metric and US customary/imperial units.