ExactUnits – Auto Unit Converter: Metric ⇄ Imperial

Converts measurements on web pages between metric and imperial units, right where you read them. Exact math. Free, no sign-up.

ExactUnits shows the measurements on any web page in the units you use. The converted value is highlighted right where the original was — hover it to see the original and the full-precision result. Pick your measurement system once; there is nothing else to set up. How to use 1. Click the ExactUnits icon and choose your measurement system: metric, US, UK or a regional one. 2. Open any page with measurements on it. 3. Each measurement is converted automatically and highlighted. 4. Hover a highlighted value to see the original and the precise result. Click it to switch back to the original text. 5. Use the switch in the popup to turn conversion on pages off and on. The converter in your toolbar Type a value, pick two units and press Convert. Paired fields take values like 5 ft 9 in. Under the fields you see what one unit equals, so the math is easy to check. Exact results are marked “=”, rounded ones “≈”. A unit that fits the number Each value is shown in the unit that reads best: a small area in square meters, a large one in hectares. Prefer your own choice? Pick Custom and set the unit for each kind of measurement. Clothing and shoe sizes The popup converts clothing sizes by garment — for women, men and kids — and shoe sizes. Sizes differ between brands, so these results are always marked as approximate. Who finds it useful Online shoppers — check how big or heavy an item from another country really is before you order. Home cooks — follow a recipe from abroad without a calculator. Travelers and expats — read distances, speeds and temperatures the way you are used to. Car and property buyers — compare specs and areas in one system. Students and engineers — exact results with the definition behind each one. Frequently asked questions Q: How exact are the results? A: Conversions use the official definitions (1 inch is exactly 2.54 cm) and exact fractions instead of floating-point approximations, so the full-precision value is right to the last digit. Q: Will it change numbers that are not measurements? A: Years, prices, ordinals and coordinates are left alone, and so are values that already show both systems. Q: Can I turn it off? A: Yes. The switch in the popup removes every conversion from open pages, and a click on a single number restores its original text. Q: Why does it ask to read and change data on all websites? A: Measurements can appear on any page, so ExactUnits needs to see the page text to find them and show the converted value in place. The text is processed in your browser and never leaves it. Q: Is my data safe? A: Pages are processed locally in your browser; their addresses and text are never sent anywhere. Once a month the extension sends anonymous usage counts, such as how many values were converted. You can turn this off in Options. All features are free during the beta. After the beta, conversion on pages will include a free daily amount, and unlimited use will need Pro — a yearly plan or a one-time purchase. The popup converter stays free. Questions or a wrong conversion? Use Feedback in the popup or write to support@smallkit.app.