Unit Converter
Free Online Unit Converter
Convert between hundreds of units across five categories: length, weight, temperature, volume, and area. Our universal unit converter handles both metric and imperial systems, performing all conversions instantly as you type. No sign-ups, no ads, and no page reloads required.
How to Use
Select a category tab (Length, Weight, Temperature, Volume, or Area). Enter a numeric value in the "From" input field and choose your source unit from the dropdown. Then select the target unit in the "To" dropdown. The converted result appears automatically. Use the swap button between the two sides to quickly reverse the conversion direction.
FAQ
How does unit conversion work?
Each unit within a category is defined relative to a base unit (e.g., meters for length, grams for weight). To convert, the input value is first converted to the base unit, then from the base unit to the target unit. Temperature conversions use special formulas instead of simple multiplication since the scales have different zero points.
Why does temperature conversion use a different method?
Temperature scales like Celsius, Fahrenheit, and Kelvin have different zero points and interval sizes. Unlike length or weight, you cannot simply multiply by a ratio. For example, to convert Celsius to Fahrenheit the formula is F = C x 9/5 + 32, which involves both multiplication and addition.
What is the difference between metric ton and imperial ton?
A metric ton (tonne) equals 1,000 kilograms or about 2,204.6 pounds. An imperial ton (long ton) equals 2,240 pounds or about 1,016 kilograms. The US short ton (not included here) equals 2,000 pounds. Always check which ton is being referenced in your context.
How accurate are the conversions?
The conversion factors used are standard values accurate to at least six significant figures. Results are displayed with up to ten significant digits of precision, which is more than sufficient for everyday use. For scientific applications requiring extreme precision, consult official NIST reference values.
Can I convert between categories?
No, conversions are only possible within the same category. You cannot convert meters to kilograms, for example, because length and weight measure fundamentally different physical quantities. Select the appropriate category tab first, then choose your units.