Unit Converter
Everyday units — length, weight, temperature, volume. No currency, no rates.
Common values
- 1 inch (in)2.54 centimetre (cm)
- 1 foot (ft)30.48 centimetre (cm)
- 1 metre (m)3.2808 foot (ft)
- 1 mile (mi)1.6093 kilometre (km)
- 1 kilogram (kg)2.2046 pound (lb)
- 1 pound (lb)453.5924 gram (g)
- 0 Celsius (°C)32 Fahrenheit (°F)
- 100 Celsius (°C)212 Fahrenheit (°F)
- 1 gallon (US)3.7854 litre (L)
How to use
- Pick the family: length, weight, temperature or volume.
- Type a number and choose the two units. The result updates as you type.
- Swap turns the pair around, so one conversion answers both directions.
Examples
A measurement from an American site
100 cm is 39.3701 in. An inch is defined as exactly 25.4 mm, so this is a definition rather than an approximation.
An oven recipe
180 °C is 356 °F. Temperature has an offset as well as a scale, which is why it cannot be done with a single multiplier.
Luggage allowance
23 kg is 50.7063 lb — just over the 50 lb line some airlines use, which is the kind of gap worth knowing before the counter.
Floor area
Pyeong is not here on purpose: it has its own converter with the exact 400/121 m² value and the usable-versus-supplied area explanation. Pyeong Converter
FAQ
Is anything uploaded?
No. The arithmetic runs in your browser and nothing is sent anywhere.
Which definitions are used?
The international ones: 1 in = 25.4 mm, 1 lb = 0.45359237 kg, 1 mile = 1609.344 m, 1 US gallon = 3.785411784 L. All exact, so a value converted and converted back comes out the same.
Why are Celsius and Fahrenheit handled differently?
Because their zero points differ. °F = °C × 1.8 + 32, not a plain multiplication — the tool uses the formula and refuses anything below absolute zero.
Are the gallons US or imperial?
US customary — gallon, fluid ounce, cup, tablespoon and teaspoon. An imperial gallon is about 20% larger, so recipes from the UK will not match.
Can it convert currency?
No, and it will not. An exchange rate changes several times a day; a converter that looks right while being out of date is worse than none.
What about pyeong and square metres?
That one has its own page, including the difference between usable and supplied floor area. Pyeong Converter