How to use the unit converter
Choose a category (length, weight, or temperature), pick the units to convert from and to, and type your value. The answer updates as you type — no button needed.
Common conversions people look up
- Celsius to Fahrenheit: ×9/5, then +32 (20°C = 68°F).
- Kilograms to pounds: ×2.205 (10 kg ≈ 22 lb).
- Kilometres to miles: ×0.621 (5 km ≈ 3.1 miles).
- Centimetres to inches: ÷2.54 (30 cm ≈ 11.8 in).
Why metric and imperial units still coexist
Most of the world uses the metric system (metres, kilograms, Celsius), standardized internationally through the International System of Units (SI). The United States, however, still primarily uses imperial units (feet, pounds, Fahrenheit) for everyday measurement, which is why conversions between the two systems come up constantly — in cooking, travel, fitness, construction, and international trade.
Understanding the three categories
- Length — covers metres, kilometres, centimetres, millimetres, miles, yards, feet, and inches. All conversions are based on a fixed ratio to metres.
- Weight — covers kilograms, grams, milligrams, pounds, ounces, and tonnes, based on a fixed ratio to kilograms.
- Temperature — unlike length and weight, temperature scales don't share a common zero point, so converting requires a formula rather than a simple multiplication (e.g., Celsius to Fahrenheit needs both a multiplication and an addition).