Free Online Unit Converter

Half the world measures in metric, the other half in imperial, and recipes, running apps, and hardware specs cheerfully mix both. This converter covers eight measurement families using exact internationally defined conversion factors, so an inch is precisely 25.4 millimetres rather than a rounded approximation.

How to use it

  1. Pick the measurement family — length, weight, temperature, area, volume, speed, time, or data.
  2. Choose your source unit and type the value.
  3. Choose the target unit; the result updates as you type.
  4. Use the swap button to reverse the direction without retyping.

Frequently asked questions

How accurate are these conversions?

They use the exact factors defined by international agreement — 1 inch = 25.4 mm, 1 pound = 0.45359237 kg, 1 mile = 1609.344 m — so accuracy is limited only by floating-point display, not by the factors themselves.

Why is temperature handled differently?

Because Celsius and Fahrenheit have different zero points, so conversion needs an offset as well as a scale factor. It cannot be done with a single multiplication like the other families.

Is a kilobyte 1000 or 1024 bytes?

This tool uses the binary convention where 1 KB = 1024 bytes, which matches how operating systems report file sizes. Storage manufacturers use the decimal 1000-byte definition, which is why a "1 TB" drive shows as roughly 931 GB.

What is the difference between a US and an imperial gallon?

They are genuinely different volumes: a US gallon is about 3.785 litres while an imperial gallon is about 4.546 litres, roughly 20% larger. Both are listed separately.

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