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Math & Units

Unit Converter

Convert between metric and imperial units — length, weight, temperature, and more.

Runs in your browserNo account requiredNo uploadFree
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About Unit Converter

Unit Converter switches a value between units across seven everyday categories — length (millimeters to miles), mass (grams to pounds), temperature (Celsius / Fahrenheit / Kelvin), volume (milliliters to gallons), area (square centimeters to acres), speed (km/h to mph), and digital storage (bytes to terabytes). It is the everyday answer to 'how many X is Y in Z?' whether you are baking, traveling, building, or coding.

Worked example: 100 km converts to 62.137 miles; 350°F converts to 176.667°C; 1 US gallon converts to 3.785 liters; 1 GB converts to 1024 MB. Pick a category, choose the source and target units, and type the value — the result is instant. Conversion factors are the exact international standard values (1 inch = 25.4 mm by definition, 1 foot = 0.3048 m, and so on), so the only rounding you see is in the displayed precision, not the math.

A few notes on edge cases. Temperature conversions use proper offset formulas — Celsius to Fahrenheit is (°C × 9/5) + 32, not a simple multiplier — which is the most common manual-conversion mistake. The gallon used here is the US gallon (3.785 L); the Imperial gallon (4.546 L) is not in the list, so for UK-style measurements you'd want a different tool. Digital storage uses binary units throughout: 1 KB = 1024 bytes, 1 MB = 1024 KB, and so on. That matches how operating systems display file sizes; disk manufacturers and networking specs use the decimal convention (1 KB = 1000 bytes), which is a few percent smaller — the same mismatch that makes a '500 GB' drive show as ~465 GB in Windows.

Conversions run entirely in your browser. Nothing about the values you convert is logged or uploaded.

Frequently asked questions

Yes. The factors used are the standard exact ratios (1 inch = 25.4 mm by definition, 1 foot = 0.3048 m). Displayed precision is rounded for readability, but the underlying math is exact.

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