Calculator
5 min read
February 13, 2026

Free Unit Converter: Length, Weight, Temperature, Speed, Area & Volume

Metric or imperial? Celsius or Fahrenheit? Here's a free tool that converts between all the units you'll ever need, instantly.

Why Unit Conversion Trips People Up

The world runs on two competing measurement systems — metric and imperial — plus specialised units for speed, area, and volume that vary by country and industry. Converting by hand means memorising dozens of multipliers, and a single misplaced decimal can throw off a recipe, a shipment, or a construction measurement.

Categories Our Converter Handles

CategoryExample units
LengthMeters, kilometers, miles, feet, inches
Weight / MassKilograms, pounds, ounces, stone, tonnes
TemperatureCelsius, Fahrenheit, Kelvin
Speedkm/h, mph, m/s, knots
AreaSquare meters, acres, hectares, square feet
VolumeLiters, gallons, cups, fluid ounces

How to Convert Units for Free

  • Open the Unit Converter
  • Pick a category — length, weight, temperature, speed, area, or volume
  • Choose your "from" and "to" units
  • Type a value and see the converted result instantly — or hit the swap button to flip direction
  • Handy Reference Conversions

  • 1 mile is approximately 1.609 kilometers
  • 1 kilogram is approximately 2.205 pounds
  • 0°C equals 32°F equals 273.15 K
  • 1 US gallon is approximately 3.785 liters
  • Frequently Asked Questions

    How precise are the conversions?

    Results use precise, internationally standardised multipliers — accurate to six decimal places.

    Does it support both US and metric units?

    Yes — every category includes both metric and imperial/US units so you can convert in either direction.

    Is there a limit to how many conversions I can do?

    No — convert as many values as you need, completely free, with no signup.

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    Written by the GMC Tools team