How to use the Unit Converter
- Choose a category
- Enter a value
- Select the from and to units to see the result
About this tool
Switch between common units instantly: kilometers to miles, kilograms to pounds, Celsius to Fahrenheit, megabytes to gigabytes and more. Results update as you type and use full precision.
Categories you can convert
- Length: meters, kilometers, centimeters, millimeters, miles, feet, inches and yards.
- Weight: kilograms, grams, milligrams, pounds, ounces, stone and tons.
- Volume: liters, milliliters, US and UK gallons, cups, fluid ounces, tablespoons and teaspoons.
- Area: square meters and kilometers, hectares, acres, square feet, inches and yards.
- Speed: m/s, km/h, mph, knots and ft/s.
- Data size: bytes to terabytes.
- Time: seconds to weeks.
- Temperature: Celsius, Fahrenheit and Kelvin.
Popular conversions
Jump straight to a dedicated converter with formula, examples and a quick table: kg to lbs, lbs to kg, tons to kg, liters to gallons, cm to inches, feet to meters, km to miles and km/h to mph. You can see every converter on the All Tools page.
Temperature formulas
- Fahrenheit = Celsius × 9 ÷ 5 + 32
- Celsius = (Fahrenheit − 32) × 5 ÷ 9
- Kelvin = Celsius + 273.15
For example, 100 °C is 212 °F and 0 °C is 32 °F.
Metric and imperial units
Most countries use the metric system (meters, kilograms, liters). The USA mainly uses US customary units (feet, pounds, gallons), and the UK uses a mix. Be careful with units that share a name but differ in size, such as the US gallon (3.785 L) and the UK gallon (4.546 L), or the metric ton (1,000 kg) and the US ton (2,000 lb). This converter lists them separately so you can choose the right one.
Frequently asked questions
Is it really free?
Yes. There are no limits, watermarks or sign-ups.
Are my files uploaded anywhere?
No. The conversion runs inside your browser, so your files never leave your device.
Are the results accurate?
Yes. Conversions use standard factors and show up to 8 significant digits.
Which categories are included?
Length, weight, temperature, data size and time.
What is the difference between a US gallon and a UK gallon?
A US gallon is about 3.785 liters and a UK (imperial) gallon is about 4.546 liters. Choose the one that matches your source.
How do I convert Celsius to Fahrenheit?
Multiply by 9, divide by 5 and add 32. For example, 20 °C is 68 °F.
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Last updated: November 6, 2026