Convertisseur d'unités
Longueur, poids, température…
À propos de cet outil
Convert between metric and imperial units across the most common categories - length, mass, volume, area, speed and temperature. All conversions run locally with full floating-point precision and rounded to a sensible number of significant digits for display.
Handy for cooking American recipes in Europe (or vice versa), travel, hobby engineering, school homework, sewing patterns translated from the wrong country, and the surprisingly common case of catalogs that list dimensions in inches when your tape measure is in millimeters.
Conversions use the standard NIST factors, so the results match what an engineer or a scientific calculator would give you. Where the two systems disagree on what a unit means - the US gallon versus the UK gallon being the classic case - both are listed separately so you can pick the right one for your context.
Fonctionnalités
- Length, mass, volume, area, speed, temperature
- Metric and US/Imperial units side by side
- Separate US and UK gallons, fluid ounces, and other ambiguous units
- Accurate temperature conversions (°C, °F, K)
- Instant, no-network conversion
- Rounded to 10 significant digits for display
Comment l'utiliser
- Pick a category from the tabs (length, mass, volume, etc.).
- Choose the source and target units from the two dropdowns.
- Type a value in either box - the converted result updates as you type, in both directions.
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Questions fréquentes
Yes - and the difference matters in cooking. A US gallon is 3.785 L; a UK (imperial) gallon is 4.546 L. The same applies to fluid ounces, quarts and pints. Both are listed separately under Volume so you can pick the right one for the recipe or product specification you're working from.
Conversions use double-precision floats and the standard NIST conversion factors, then round to 10 significant digits for display. That's far more precision than any practical use case needs - you'll see exactly the same numbers you'd get from a scientific calculator.
Because the temperature scales don't share a zero point. Celsius and Fahrenheit have different zero offsets, and Kelvin offsets from Celsius by 273.15. The tool handles the offsets automatically so you don't have to remember the formulas.
Those have their own dedicated tools because their rates and rules change over time - currency moves daily and time zones depend on the IANA database. See the Currency and Time Zone tools in the Everyday section.