📏 Unit Converter

Free online unit converter

Convert between common units of length, weight and temperature in a single step. Choose a category, type a value, pick the unit you are converting from and the unit you want, and the answer appears instantly and updates as you type. It covers metric and imperial units, so it is useful for cooking, travel, shopping abroad, school work, DIY projects and anything else where measurements do not match.

How to use it

1. Select a category: Length, Weight or Temperature.
2. Enter the value you want to convert.
3. Choose the starting unit in the first drop-down and the target unit in the second.
4. Read the result in the box below.

Units included

• Length: meters, kilometers, centimeters, millimeters, miles, yards, feet and inches.
• Weight: kilograms, grams, milligrams, pounds, ounces and metric tonnes.
• Temperature: Celsius, Fahrenheit and Kelvin.

Useful conversion facts

• 1 inch is exactly 2.54 centimeters.
• 1 mile is exactly 1.609344 kilometers.
• 1 foot is exactly 0.3048 meters.
• 1 pound is exactly 0.45359237 kilograms.
• 1 ounce is about 28.35 grams.
• 1 metric tonne is 1,000 kilograms.

How temperature conversion works

Temperature scales do not simply multiply, because their zero points differ. To convert Celsius to Fahrenheit, multiply by 9, divide by 5 and add 32. To convert Fahrenheit to Celsius, subtract 32, then multiply by 5 and divide by 9. Kelvin equals Celsius plus 273.15, and 0 Kelvin is absolute zero, the lowest possible temperature. Water freezes at 0 degrees Celsius (32 Fahrenheit) and boils at 100 degrees Celsius (212 Fahrenheit) at sea level.

Tips for accurate conversions

• For cooking, weigh ingredients when you can. Cups and spoons vary between countries, and this tool does not convert volume.
• Round the result sensibly. Results are shown with up to ten significant digits, which is more precise than most real measurements.
• Double-check units that sound alike, such as ounces (weight) and fluid ounces (volume).

Frequently asked questions

Does it convert volume, area or speed?

Not yet. The current categories are length, weight and temperature, and more may be added later.

Why do I see many decimal places?

Some conversions, such as inches to meters, do not divide evenly. You can round the result to the precision you need.

Is the tool exact?

It uses the internationally agreed definitions for each unit, so the conversion factors are exact or very close to it. Small differences can still appear from rounding in the display.

Is my data stored?

No. Conversions run in your browser and nothing is saved.