Unit Converter
Convert length, weight, volume, temperature, area and speed between metric and imperial units instantly, with the formula shown.
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About this tool
This unit converter converts between metric and imperial units in six everyday categories. Choose a category, type a value and pick the two units: the result appears as you type, together with the formula, so you know exactly how it was calculated. Swap the units with one click, use the quick value presets, and look back at earlier conversions in the history.
Supported categories and units
- Length: millimeter, centimeter, meter, kilometer, inch, foot, yard, mile and nautical mile.
- Weight: milligram, gram, kilogram, metric ton, US ton, ounce, pound and stone.
- Volume: milliliter, liter, cubic meter, teaspoon, tablespoon, and US fluid ounces, cups, pints, quarts and gallons.
- Temperature: Celsius, Fahrenheit, Kelvin and Rankine.
- Area: square centimeter, square meter, square kilometer, hectare, square inch, square foot, square yard, acre and square mile.
- Speed: meters per second, kilometers per hour, miles per hour, feet per second, knots and Mach.
How to convert units
- Select the category, for example Length.
- Enter the value you want to convert.
- Choose the unit you are converting from and the unit you want.
- Read the result and the formula. Click the swap button to convert the other way.
Common conversions
| From | To | Multiply by |
|---|---|---|
| Inches | Centimeters | 2.54 |
| Feet | Meters | 0.3048 |
| Miles | Kilometers | 1.609344 |
| Pounds | Kilograms | 0.45359237 |
| US gallons | Liters | 3.785411784 |
| Miles per hour | km/h | 1.609344 |
Temperature is the exception: it is not a simple multiplication. Fahrenheit = Celsius x 9/5 + 32, and Kelvin = Celsius + 273.15.
Tips for accurate conversions
- US and UK units differ for volume: a US gallon is 3.785 liters, an imperial gallon 4.546 liters.
- Keep extra decimals while you calculate and round only the final answer.
- Check the unit symbol: "oz" can mean weight ounces or fluid ounces.
Need one conversion quickly? Dedicated pages such as cm to inches, kg to lbs and Celsius to Fahrenheit include ready conversion tables.
Frequently asked questions
Which units can I convert?
Length, weight, volume, temperature, area and speed, with more than 50 metric and imperial units in total, from millimeters and ounces to acres, knots and Kelvin.
How do I convert centimeters to inches?
Divide the number of centimeters by 2.54. For example, 30 cm is 30 / 2.54 = 11.81 inches. Choose Length, then centimeter to inch, and the tool does it for you.
How do I convert Celsius to Fahrenheit?
Multiply by 9/5 and add 32. So 20 °C is 20 x 1.8 + 32 = 68 °F.
How many kilograms is a pound?
One pound is exactly 0.45359237 kilograms, so 150 lb is about 68.04 kg.
Is a US gallon the same as a UK gallon?
No. A US gallon is about 3.785 liters and an imperial (UK) gallon is about 4.546 liters.
Does the converter save my history?
Yes, recent conversions are listed in the history on the page so you can look back at them. Nothing is sent to a server.