How to use it
- Pick a quantity, such as Length or Weight.
- Type the value and choose the From and To units.
- Read the result and the conversions to every other unit.
- Change the decimal places or copy the result.
What you can convert
The converter covers twelve quantities. Each tab has its own list of units:
| Quantity | Example units |
|---|---|
| Length | in, ft, yd, mi, mm, cm, m, km, nautical mile |
| Weight | oz, lb, stone, g, kg, metric ton, troy ounce, carat |
| Area | sq in, sq ft, sq yd, acre, m², hectare, km² |
| Volume | tsp, tbsp, fl oz, cup, pint, quart, gallon, mL, L, m³, oil barrel |
| Temperature | °F, °C, K |
| Speed | mph, km/h, m/s, knot |
| Running pace | min/mile, min/km |
| Time | ms, second, minute, hour, day, week, month, year |
| Data size | byte, kB, MB, GB, TB, KiB, MiB, GiB |
| Energy | J, kJ, kcal, Wh, kWh |
| Power | W, kW, hp, metric hp |
| Pressure | Pa, kPa, bar, atm, psi, mmHg |
When a quantity has more than two units, you also get the value in every other unit at once, so you don't have to convert one pair at a time.
Exact definitions, not rounded factors
US customary units are defined in terms of metric units, and the converter uses those exact definitions:
- 1 inch = 2.54 cm
- 1 foot = 0.3048 m
- 1 yard = 0.9144 m
- 1 mile = 1,609.344 m
- 1 pound = 0.45359237 kg
- 1 ounce = 28.349523125 g
- 1 US gallon = 3.785411784 L
Because the factors are exact, results only get rounded at the very end, to the number of decimal places you pick (0 to 8). Very large or very small results switch to scientific notation so you never see a misleading 0.
US vs. imperial units
Some units share a name but not a size. The converter lists them separately so you can pick the right one:
| Unit | US | UK (imperial) |
|---|---|---|
| Gallon | 3.785 L | 4.546 L |
| Pint | 473 mL | 568 mL |
| Fluid ounce | 29.57 mL | 28.41 mL |
If a recipe, a gas price or a fuel economy figure comes from the US, it uses US units. British sources usually mean imperial pints and gallons.
Temperature works differently
Most units convert by multiplying by a factor. Temperature scales also have different zero points, so the converter goes through kelvin:
- °F = °C × 9/5 + 32
- °C = (°F − 32) × 5/9
- K = °C + 273.15
Example: 72 °F is (72 − 32) × 5/9 = 22.2 °C. For a dedicated page with a reference chart, use the Celsius to Fahrenheit converter.
Tips for common conversions
- Height in feet and inches? The height converter takes 5′10″ directly.
- Recipes in cups? Cups measure volume, not weight. To turn cups of flour into grams, use the cups to grams converter.
- Hard drive sizes: a "1 TB" drive has 10¹² bytes, which your computer may show as about 931 GiB. Both numbers are correct; they use different units.
- Calories on food labels are kilocalories (kcal).
Everything runs in your browser, and nothing you type is sent anywhere.
Frequently asked questions
How many centimeters are in an inch?
Exactly 2.54 cm. The inch has been defined that way since 1959.
How do I convert pounds to kilograms?
Multiply by 0.45359237, or roughly divide by 2.2. For example, 150 lb is about 68.04 kg.
Is a US gallon the same as a UK gallon?
No. A US gallon is 3.785 liters and a UK (imperial) gallon is 4.546 liters, about 20% larger.
Why does my 1 TB drive show less space?
Drive makers use decimal units (1 TB = 1,000,000,000,000 bytes), while many operating systems report binary units (1 TiB = 1,099,511,627,776 bytes). 1 TB is about 0.909 TiB, often shown as 931 GB.
Can I convert running pace?
Yes. The Running pace tab converts minutes per mile to minutes per kilometer and back. Enter the pace in decimal minutes, so 8:30 is 8.5.
Does this converter work offline?
Once the page has loaded, all conversions run in your browser without contacting a server, so they keep working even if your connection drops.
Last updated: November 12, 2026