Instant unit conversions for length, weight, temperature, volume and more. Complete conversion tables. No signup.
This unit converter runs entirely in your browser — no data is ever sent to a server. As a measurement converter, it covers every common unit from metric to imperial: inches to cm, kg to lbs, miles to km, Fahrenheit to Celsius, and much more. The instant conversion table below the main converter answers every variant of your unit conversions question on a single page.
Every unit of measurement belongs to a system — and most of the world uses two competing systems simultaneously. The International System of Units (SI), commonly called the metric system, is the global standard used by science, medicine, engineering, and everyday life in nearly every country. The United States, along with Myanmar and Liberia, primarily uses the US customary system, which traces its roots to English units that date back centuries. The result is a world where the same physical quantity — a person's weight, a road distance, a recipe measurement — is expressed differently depending on where you are.
Unit conversion bridges this gap by applying mathematically exact relationships between units. Many of these relationships are defined by international agreement: 1 inch is defined as exactly 2.54 centimeters, 1 pound is exactly 453.59237 grams, 1 US gallon is exactly 3.785411784 liters. These definitions are not approximations — they are fixed by treaty and maintained by international standards organizations including the International Bureau of Weights and Measures (BIPM) and the US National Institute of Standards and Technology (NIST). Converting between units within the same category is a matter of multiplying by the correct ratio, which this tool does instantly as you type.
Temperature is a special case because the Celsius and Fahrenheit scales are offset, not just scaled — they use different zero points. Converting between them requires both a multiplication and an addition: °F = (°C × 9/5) + 32. Fuel economy is another special case: miles per gallon (MPG) and liters per 100 kilometers (L/100km) are inversely related, meaning better efficiency means a higher MPG but a lower L/100km number. This converter handles both special cases automatically.
The converter covers 14 categories and over 100 individual units. The full conversion table below the input field shows your value converted to every unit in the selected category simultaneously — so you can see, for example, that 5 feet equals 60 inches, 1.524 meters, and 152.4 centimeters all at once, without switching between pages or doing multiple lookups.
Enter your value in the input field, select the unit you are converting from in the dropdown, then select the unit you want to convert to. The result appears instantly. You can also see all unit conversions at once in the table below the main converter.
Yes, completely free. No account, no signup, no file size limits, no watermarks. The tool is ad-supported to remain free for everyone.
No. unitconversions.app is a fully client-side tool. All unit conversions happen entirely in your browser using pure JavaScript math — no data is ever sent to a server. You can disconnect from the internet after the page loads and the tool will still work.
All conversions use internationally accepted conversion factors. For example, 1 inch = exactly 2.54 cm, 1 pound = exactly 0.45359237 kg. Results are displayed to up to 6 significant figures, which is more than sufficient for everyday use.
unitconversions.app supports 14 categories: Length, Weight/Mass, Temperature, Volume, Area, Speed, Time, Digital Storage, Pressure, Energy, Frequency, Angle, Fuel Economy, and Cooking. Each category page includes a full conversion table showing all units at once.