Unit Converter
This converter handles the three unit families people look up most: length, weight and temperature, across both metric and imperial systems. Pick a category, choose the units you are converting from and to, and enter a value to get an instant, precise result.
How to use the unit converter
- Choose a category: length, weight or temperature.
- Pick the unit you are converting from and the unit you want, from the two drop-downs (only units from the chosen category are shown).
- Enter the value to convert and read the result.
Formula
Length and weight conversions multiply the value by a fixed ratio between the two units (for example 1 mile = 1,609.344 metres). Temperature is not a simple ratio: Celsius to Fahrenheit is °F = °C × 9/5 + 32, Celsius to Kelvin is K = °C + 273.15, and the other directions reverse these formulas.
Worked examples
Length
1 mile converts to 1,609.344 metres, or about 1.609 kilometres.
Weight
1 kilogram converts to about 2.205 pounds.
Temperature
0°C converts to 32°F, and 100°C converts to 212°F — the freezing and boiling points of water at sea level.
Quick-reference conversion table
For the conversions people look up most often, here are the key ratios at a glance — this converter calculates from the original value every time, but these are handy to remember:
| Conversion | Ratio |
|---|---|
| 1 kilometre | 0.6214 miles |
| 1 mile | 1.609 kilometres |
| 1 metre | 3.281 feet / 39.37 inches |
| 1 foot | 0.3048 metres / 30.48 cm |
| 1 kilogram | 2.205 pounds |
| 1 pound | 0.4536 kilograms |
| 1 metric tonne | 1,000 kg / 2,204.6 lb |
Most of the world uses the metric system (SI units), standardised internationally since 1960 because it scales cleanly in powers of 10. The United States is the largest economy still using imperial units (feet, pounds, Fahrenheit) for everyday measurement, which is why conversions between the two systems come up constantly in trade, travel, cooking and engineering.
Common mistakes to avoid
- Treating temperature like length or weight and multiplying by a ratio — Celsius, Fahrenheit and Kelvin scales have different zero points, so they need the full formula, not just a multiplier.
- Confusing a short ton (US, 2,000 lb), long ton (UK, 2,240 lb) and metric tonne (1,000 kg) — this converter uses the metric tonne.
- Rounding too early in multi-step conversions, which compounds small errors — this tool always calculates from the original value.
Frequently asked questions
How do I convert Celsius to Fahrenheit?
Multiply by 9/5 (1.8) and add 32: °F = °C × 1.8 + 32. So 20°C = 20 × 1.8 + 32 = 68°F.
How many pounds are in a kilogram?
About 2.20462 pounds. So 10 kg is about 22.05 lb.
What is the difference between a mile and a kilometre?
A mile is longer: 1 mile equals 1.609 kilometres, so 5 km is a little over 3 miles (3.107 miles).
Is a metric tonne the same as a US ton?
No. A metric tonne is 1,000 kg (about 2,204.6 lb). A US short ton is 2,000 lb (about 907.2 kg). This converter uses the metric tonne.
Reviewed September 29, 2026 by the CalcSolver editorial team. Found a mistake? Tell us; see our editorial policy.