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Convert values between metric, imperial, US customary and other commonly used units. Choose a measurement category, enter your value and get an instant conversion with the formula and calculation steps.
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Need a quick conversion? Enter a value, choose the units you want to convert from and to, and see the result instantly.
Converter Categories
Find conversion tools by measurement type. Each category includes commonly used converters, formulas and reference values for everyday, academic, scientific and technical calculations.
Popular Converters
Start with some of the conversions people use most often. Choose a converter to calculate a value and view the formula, worked example and common conversion table.
Unit Converter is a set of free conversion tools. Each converter page shows the number you asked for, plus the formula, the working and a table of common values, so you can check the answer instead of taking it on trust.
It covers metric, imperial and US customary units for temperature, mass, length, volume, area, speed, pressure, energy, data storage and time.
Unit conversion appears in many everyday situations. Recipes may use cups while ingredients are measured in millilitres or grams. Travel information can show kilometres while another country uses miles. Weather forecasts may report Celsius or Fahrenheit. Fitness devices can display kilometres, miles, kilograms or pounds.
Students and engineers frequently move between measurement systems when solving scientific and technical problems. Data professionals work with storage units and transfer speeds, while construction, manufacturing and logistics commonly require length, area, volume, mass and pressure conversions.
Unit conversions work by applying a defined mathematical relationship between compatible measurement units. Where a relationship is defined exactly, our converters use that defined value during calculation and round only the displayed result when needed.
For example, one inch is exactly 2.54 centimetres. Converting 10 inches to centimetres therefore requires multiplying 10 by 2.54:
Each converter includes the formula used, calculation steps and useful reference values so you can see how the result was calculated.
Unit Converter uses established measurement relationships for its calculations. Some conversions are based on exact definitions, while others may produce repeating decimals that must be rounded for display.
When additional precision is useful, our converters retain more decimal places during the calculation before presenting the final result. The individual converter page also explains the formula and unit convention used.
Common Conversion Formulas
| Conversion | Formula |
|---|---|
| Celsius → Fahrenheit | °F = (°C × 9/5) + 32 |
| Fahrenheit → Celsius | °C = (°F − 32) × 5/9 |
| Kilograms → Pounds | lb = kg × 2.2046226218 |
| Pounds → Kilograms | kg = lb × 0.45359237 |
| Centimetres → Inches | in = cm ÷ 2.54 |
| Inches → Centimetres | cm = in × 2.54 |
| Kilometres → Miles | mi = km × 0.6213711922 |
| Miles → Kilometres | km = mi × 1.609344 |
| Metres → Feet | ft = m × 3.280839895 |
| Litres → US Gallons | US gal = L × 0.2641720524 |
| km/h → mph | mph = km/h × 0.6213711922 |
| GB → MB | MB = GB × 1,000 |
| GiB → MiB | MiB = GiB × 1,024 |
Conversion results may be displayed with fewer decimal places for readability. Converter pages can provide additional precision where required.
Yes. Unit Converter uses standard mathematical formulas and commonly accepted conversion factors for metric, imperial, US customary, and scientific unit conversions.
Yes. Unit Converter is free to use for online unit conversions. You can convert values instantly without registration.
Yes. Our tools support integers and decimal values, making them useful for cooking, science, engineering, shipping, fitness, and everyday measurements.
We support many conversion categories including temperature, weight, length, volume, area, speed, pressure, power, energy, data storage, data speed, time, angle, force, fuel economy, and number system conversions.
Some of the most popular tools are Celsius to Fahrenheit, Kilograms to Pounds, Centimeters to Inches, Meters to Feet, and Liters to Gallons.
No. Unit Converter works directly in your browser. You can use the website on desktop, mobile, or tablet without installing an app.