Unit Converter
Convert length, weight, temperature, and more.
The Unit Converter turns a measurement from one unit into another in seconds. Pick a category, type in your number, choose the unit you have and the unit you want, and read the result. It handles four everyday categories: length (mm, cm, m, km, in, ft, yd, mi), mass (mg, g, kg, t, oz, lb), temperature (Celsius, Fahrenheit, Kelvin), and volume (ml, l, cubic meters, tsp, tbsp, cup, gallon).
Use it when a recipe lists grams but your scale reads ounces, when a package weight shows kilograms and you think in pounds, or when a forecast gives Celsius and you want Fahrenheit. It is handy for schoolwork, travel, cooking, DIY projects, and shipping. Common lookups include kg to lb, cm to inches, and Celsius to Fahrenheit.
Result
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How to use the unit converter
- Choose a category: length, mass, temperature, or volume.
- Enter the value you want to convert in the input box.
- Select the unit you are starting from in the From menu.
- Select the unit you want in the To menu.
- Read the converted result, and switch From and To if you need the reverse.
Worked example
Say you have a suitcase that weighs 23 kg and the airline lists limits in pounds. Choose the mass category, enter 23, set From to kg and To to lb. Since one kilogram equals about 2.20462 pounds, 23 multiplied by 2.20462 gives roughly 50.7 lb. Now you can see it is just over a common 50 lb limit. For temperature the math is different: to change 20 degrees Celsius to Fahrenheit, multiply by 9/5 and add 32, which gives 68 degrees Fahrenheit.
Common mistakes to avoid
- Choosing the wrong category, such as trying to convert liters using the mass menu instead of volume.
- Treating temperature like a simple multiplication; Celsius, Fahrenheit, and Kelvin need an offset as well as a factor.
- Mixing up US and imperial gallons, which are different sizes, so confirm you mean US gallons.
- Confusing weight units like ounces with fluid ounces, which measure volume, not mass.
- Swapping the From and To units by accident, which flips the result the wrong way.
Frequently asked questions
How accurate are the conversions?
We use standard conversion factors; results are rounded for display but computed at full precision.
Why does temperature not use a simple conversion factor?
Length and mass scales all start at zero, so you multiply by one number. Temperature scales start at different points, so converting Celsius to Fahrenheit means multiplying by 9/5 and then adding 32. Kelvin shifts the Celsius scale by 273.15 degrees. The converter applies these offsets for you automatically.
Can I use this to work out a percentage change between two measurements?
Convert both values to the same unit first, then compare them with our <a href="/tools/percentage-calculator/">Percentage Calculator</a>. For example, convert two weights to kilograms, then find the percentage difference between them for a clean, accurate comparison.
What is the difference between mass and weight here?
In everyday use the terms overlap, and units like kilograms and pounds are listed under mass because that is how scales and labels report them. Strictly, weight depends on gravity while mass does not, but for cooking, shipping, and daily tasks the converter gives the numbers you expect.