About this tool
Convert length, weight, temperature and speed.
The Unit Converter handles the most common physical measurement categories. Enter a value in any unit and all others in that category update simultaneously — no need to remember conversion formulas. Categories: length (mm, cm, m, km, in, ft, yd, mi), mass (mg, g, kg, t, oz, lb, st), temperature (°C, °F, K), and speed (m/s, km/h, mph, knots).
Example
100 km → 62.137 miles · 160.934 km/h (when speed selected)
How to use
- Select a category (Length, Mass, Temperature, Speed).
- Enter a value in any unit field.
- All other units update simultaneously.
- Copy any result.
Features
- Length: mm, cm, m, km, in, ft, yd, mi
- Mass: mg, g, kg, t, oz, lb, st
- Temperature: °C, °F, Kelvin
- Speed: m/s, km/h, mph, knots
- All units at once
Frequently Asked Questions
What categories are covered?+
Length, mass/weight, temperature and speed. For more detailed weight conversions see the Weight Converter; for data storage sizes see the Data Size Converter.
How is temperature conversion done?+
°C to °F: multiply by 9/5 then add 32. °C to K: add 273.15. Both directions apply the correct inverse formulas.
Can I convert imperial to metric?+
Yes. Type the value in an imperial field (inches, feet, pounds, etc.) and the metric equivalents update immediately.
Are the conversions accurate?+
Conversions use standard SI definitions accurate to 15–16 significant figures (JavaScript float64 precision).
Which unit categories are supported?+
Length (mm to km, inches to miles), weight (mg to tonnes), temperature (°C, °F, K), speed (mph, km/h, m/s, knots).
Does it convert imperial to metric?+
Yes — bidirectionally. Enter any value in any unit and all other units update simultaneously.