Unit converter
Length, weight, temperature, volume, area, speed, time and data.
Convert between the units you actually run into: centimetres and inches, kilos and pounds, Celsius and Fahrenheit, litres and gallons, square metres and acres, km/h and mph, plus time and storage units. Conversion is instant and works both ways.
How to use
- Pick the category: length, mass, temperature, volume, area, speed, time or data.
- Select source and target units in the two dropdowns.
- Type a value on either side — conversion works both ways.
The conversions people need most
Inches to centimetres (1 in = 2.54 cm exactly) covers TVs, monitors and bike wheels. Pounds to kilos (1 lb = 0.4536 kg) covers labels and recipes. Miles to kilometres (1 mi = 1.609 km) covers running and travel.
Temperature is not a ratio
Unlike other units, temperature does not convert by a simple factor, because the scales have different zeros: °F = °C × 1.8 + 32 and K = °C + 273.15. That is why 0 °C is 32 °F, not 0 °F.
Kitchen and storage units
Cup, tablespoon and teaspoon follow the metric standard (240 ml, 15 ml and 5 ml). For storage we use the binary convention (1 KB = 1024 bytes), the one your operating system shows for file sizes — handy when you need to compress a PDF to fit an attachment limit.
Frequently asked questions
How many centimetres in an inch?
Exactly 2.54 cm — that is a definition, not a rounding. That is why a 50-inch TV has a 127 cm diagonal.
How do I convert Celsius to Fahrenheit in my head?
Multiply by 1.8 and add 32. For a quick estimate: double and add 30. The calculator does the exact maths, Kelvin included.
How many pounds in a kilo?
About 2.2046 pounds. The other way round, one pound is 0.4536 kg.
Why is 1 KB 1024 bytes and not 1000?
Because computing counts in powers of two. We use the binary convention (1 KB = 1024 B), the one Windows and most systems show for file sizes.