Unit Converter
Convert any unit to any other in 22 categories — length, weight, temperature, volume, area, speed, time, energy, power, pressure, data storage, data rate, frequency, angle, fuel economy, force, plus acceleration, torque, density, flow rate, typography (CSS px / pt / em / rem), and electric charge (mAh / Ah). 250+ units, exact conversion factors, formulas shown for every result. All in your browser — nothing leaves your device.
Length
9 units| Unit | Symbol | Value |
|---|
Frequently asked questions
Multiply the value in centimeters by 0.3937 to get inches. For example, 10 cm × 0.3937 = 3.937 in. Equivalently, divide by 2.54 since 1 inch is exactly 2.54 centimeters.
Multiply kilograms by 2.20462. For example, 70 kg × 2.20462 = 154.32 lb. To go the other way, multiply pounds by 0.453592 (or divide by 2.20462). The relationship is exact: 1 pound ≡ 0.45359237 kg by international agreement.
Multiply Celsius by 9/5 and add 32: °F = °C × 9/5 + 32. For example, 20°C × 9/5 + 32 = 68°F. To go from Fahrenheit to Celsius: °C = (°F − 32) × 5/9.
1 US gallon = 3.78541 liters. 1 UK (Imperial) gallon = 4.54609 liters. The US gallon is smaller; when in doubt, assume US gallons unless the source is from the UK. We expose both — see the Volume category.
Multiply miles by 1.609344. For example, 60 mph × 1.609344 = 96.56 km/h. To go from kilometers to miles, multiply by 0.621371. A rough mental shortcut: km ≈ miles × 1.6.
In the decimal / SI standard used by storage manufacturers, 1 MB = 1,000,000 bytes. In the binary standard used by RAM and operating systems, 1 MiB (mebibyte) = 1,048,576 bytes (220). We expose both — pick MB for marketing / storage capacity, MiB for RAM and OS reports.
Mbps is megabits per second (1 Mb = 1,000,000 bits). MB/s is megabytes per second (1 MB = 1,000,000 bytes = 8,000,000 bits). So 100 Mbps internet ≈ 12.5 MB/s download. Always divide Mbps by 8 to get the practical file-transfer rate.
Fuel-economy units are inversely related, so it isn't a simple multiplication. Use 235.215 / mpg = L/100km. For example, 30 mpg → 235.215 / 30 ≈ 7.84 L/100km. To go the other way: 235.215 / (L/100km) = mpg.
Multiply pound-force feet by 1.35582 to get newton-meters. For example, 100 lbf·ft × 1.35582 = 135.58 N·m. To go from N·m to lbf·ft, multiply by 0.737562 (or divide by 1.35582). Engine torque specs commonly need this — a 300 lbf·ft pickup truck makes 407 N·m.
At the standard CSS resolution of 96 DPI, 1 pt = 4/3 px ≈ 1.333 px. So 12 pt = 16 px, which is also the default em / rem value in browsers. To go the other way: 1 px = 0.75 pt. Web designers usually work in px and rem; print designers in pt and pc (1 pc = 12 pt).
Divide milliampere-hours by 1000: 5000 mAh = 5 Ah. To go from Ah to mAh, multiply by 1000. Note that mAh / Ah are charge units; to convert to energy (Wh), multiply by the battery voltage: a 5000 mAh × 3.7 V phone battery stores 18.5 Wh.
Yes. All conversions run as plain JavaScript in your browser. No API call, no upload, no signup. Once the page is loaded, you can disable your internet and the converter still works.
We use the internationally-defined exact conversion factors where they exist (e.g., 1 inch ≡ 2.54 cm exactly, 1 pound ≡ 0.45359237 kg exactly), and high-precision SI values everywhere else. Results are accurate to JavaScript's double-precision floating-point limit (≈15 significant digits).
About this converter
This tool is built for one job: convert any unit to any other, fast, with no signup and no upload. It covers 16 measurement categories and over 200 individual units — the ones you actually need day-to-day, including a few specialist ones (nautical mile, mebibyte, kilocalorie, foot-pound).
How it works
Every category has a base unit (meter for length, kilogram for weight, kelvin for temperature, etc.). Each unit declares a factor or function that maps it to and from the base. To convert, the input is mapped to the base, then mapped to the target unit. This single-pivot approach is robust and avoids cumulative rounding errors that hand-converting via intermediate units can introduce.
Temperature is special — it has an additive offset (0°C is not the same temperature as 0°F), so its conversions are defined as small functions rather than multipliers. Fuel economy is even more special: mpg and L/100km are inversely proportional, so they need their own pair of reciprocal functions.
Exact vs approximate factors
Where the international system defines an exact equivalence (1 inch ≡ 2.54 cm by NIST, 1 pound ≡ 0.45359237 kg by 1959 international agreement, 1 nautical mile ≡ 1852 m), the tool uses the exact value. Everywhere else (e.g., 1 BTU ≈ 1055.06 J) it uses the most-published SI value at full double-precision. Floating-point arithmetic limits the result to ~15 significant digits regardless.
Privacy
No data leaves your browser. The tool is a single HTML file with embedded JavaScript — no API, no telemetry, no third-party tracker. Even the math runs synchronously, on the main thread, with zero network activity after the initial page load.