Online metric and imperial unit converter
Use this all-in-one unit converter to calculate equivalent measurements for length, mass, area, volume, speed, digital storage, time, and temperature. Results update instantly as you type, making it useful for study, travel, recipes, shipping, fitness, construction estimates, and everyday international measurements.
How to convert measurement units
- Choose the measurement category that matches the quantity.
- Enter a number and select its current unit in the From menu.
- Choose the required unit in the To menu to see the conversion.
- Use the swap button to reverse the direction, or copy the complete result statement.
Available conversion categories
Length: mm, cm, metres, kilometres, inches, feet, yards, and miles.
Mass: mg, grams, kilograms, ounces, pounds, and metric tonnes.
Area and volume: square units, acres, hectares, litres, cups, fluid ounces, and gallons.
Speed and time: m/s, km/h, mph, knots, seconds, minutes, hours, days, and weeks.
Temperature: Celsius, Fahrenheit, and Kelvin.
Data storage: decimal KB/MB/GB and binary KiB/MiB/GiB.
How conversions are calculated
Most measurements are converted through a standard base-unit factor. Temperature uses separate offset formulas because zero Celsius, zero Fahrenheit, and zero Kelvin do not represent the same point. Digital storage distinguishes decimal units based on powers of 1000 from binary units based on powers of 1024. Displayed answers may be rounded for readability while calculations retain greater precision.
Examples of common conversions
One kilometre equals 1,000 metres, one inch equals exactly 2.54 centimetres, one pound equals 0.45359237 kilograms, and one US gallon equals approximately 3.78541 litres. For formal engineering, laboratory, medical, or regulated trade work, confirm the result against the standard required by your industry.