Unit Converter
Unit Converter translates a numeric value between two compatible units. Choose a measurement category first so only units of the same physical quantity are compared.
What it does
The tool covers common metric and customary units across several categories. Most conversions multiply by a fixed scale factor; temperature requires an offset as well as a scale.
Unit conversion changes the representation, not the underlying quantity. For example, one metre and 100 centimetres describe the same length.
How to use this tool
- Choose a category: Select the kind of measurement, such as length, weight, temperature, area, volume, speed, time, or data.
- Enter the source value: Type the number and select the unit it currently uses.
- Choose the destination unit: Select the unit you need; the converted value updates automatically.
- Copy with its unit: Record both the result and destination symbol to avoid ambiguity.
Input and output
Input
- Measurement category
- Numeric value
- From unit and To unit
Output
- Converted value in the selected destination unit
How it works
Scale conversions
Length, mass, area, volume, speed, time, and data values are normalized to a base unit, then scaled to the target.
Temperature conversions
Celsius, Fahrenheit, and Kelvin use formulas with offsets; zero in one scale is not zero in the others.
Practical example
- Scenario
- Convert a 5 kilometre run to miles.
- Action
- Select the two units and enter 5.
- Input
- Category: Length; value: 5; from: km; to: mi
- Expected result
- Approximately 3.10686 miles.
Limitations
- Only units listed in the selected category are supported.
- Results use mathematical conversion constants and may show more precision than the input justifies.
- Weight is used in the everyday sense of mass; scientific force calculations require local gravity.
- Data-unit conventions can differ: decimal kB/MB and binary KiB/MiB are not interchangeable.
Frequently Asked Questions
Can I convert between unrelated units?
No. A length cannot be converted to a mass because they measure different physical quantities.
Why is temperature not converted by simple multiplication?
The scales have different zero points, so Celsius and Fahrenheit require both scaling and an offset.
How many decimal places should I keep?
Do not claim more significant figures than the source measurement supports.
Are metric tons and US tons the same?
No. Check the exact unit label; similarly, US and imperial volume units can differ.