Convert between units of length, weight, volume, temperature, area, speed, time, data, pressure, and energy. Pick a category, type a value, and choose your units — the result updates as you type. Use the swap button to flip the conversion direction.
How unit conversion works
Every category has a base unit (for length it is the meter, for weight the kilogram). Each unit is defined by how many base units it equals, so a conversion is two steps: multiply your value by the source unit factor to get the base amount, then divide by the target unit factor. Temperature is the exception — because each scale has a different zero point, the calculator converts through Celsius rather than using a single multiplier.
Common conversions
| From | To | Multiply by |
|---|---|---|
| Inches | Centimeters | 2.54 |
| Miles | Kilometers | 1.609 |
| Pounds | Kilograms | 0.4536 |
| US gallons | Liters | 3.785 |
| Square feet | Square meters | 0.0929 |
| Miles per hour | Kilometers per hour | 1.609 |
| PSI | Kilopascals | 6.895 |
For full printable lookup tables, see the Metric Conversion Chart, Length Conversion Chart, and Temperature Conversion Chart.
FAQ
How do I convert Fahrenheit to Celsius? Subtract 32, then multiply by 5/9. So 212°F becomes (212 − 32) × 5/9 = 100°C. The calculator does this automatically when you pick Temperature.
Why does a very large or very small result show in scientific notation? Numbers below 0.0001 or at or above one billion are shown in exponential form so the answer stays readable. See the Scientific Notation Chart for how to read it.
Are US and Imperial gallons the same? No. A US gallon is about 3.785 liters and an Imperial (UK) gallon is about 4.546 liters, so they are listed separately under Volume.