The Calculator Helper

Unit Converter

Convert length, weight and temperature between metric and imperial.

Result
0

    Accurate everyday conversions

    Length and weight conversions use exact internationally agreed factors — for example one inch is exactly 2.54 centimetres and one pound is exactly 453.59237 grams. Temperature is converted through the standard formulas rather than a simple ratio.

    °F → °C(°F − 32) × 5 ÷ 9
    °C → °F(°C × 9 ÷ 5) + 32
    °C → K°C + 273.15
    Worked example

    One mile equals 1,609.344 metres, so 10 km divided by 1.609344 is about 6.21 miles. For temperature, 100 degrees Celsius converts to 100 times 9/5 plus 32, which is 212 degrees Fahrenheit.

    Exact figures versus everyday rounding

    Many conversions are defined exactly — one inch is precisely 2.54 centimetres, one pound exactly 453.59237 grams — so the only real question is how many decimal places you need. For a recipe or a wall measurement, rounding to a sensible figure is fine; for engineering or medicine, keep the precision.

    Conversions worth memorising

    • 1 inch ≈ 2.54 cm · 1 foot ≈ 30.5 cm · 1 mile ≈ 1.61 km
    • 1 kg ≈ 2.2 lb · 1 litre ≈ 0.26 US gallon
    • °C to °F: multiply by 1.8, then add 32

    Frequently asked questions

    Are these conversions exact?
    Length and weight use exact internationally defined factors, such as 1 inch equals 2.54 cm and 1 pound equals 453.59237 g. Temperature uses the standard conversion formulas.
    Why isn't temperature a simple ratio?
    The Celsius and Fahrenheit scales have different zero points, so you convert through a formula rather than multiplying by a single factor.
    What is the difference between mass and weight?
    In everyday use kilograms and pounds are treated as the same kind of quantity. Strictly, mass is constant while weight depends on gravity, but for ordinary conversions the distinction does not matter.
    Can I convert between metric and imperial?
    Yes. Every unit converts through a common base, so you can freely mix systems, for example centimetres to inches or kilograms to pounds.