Unit converter
Turn feet into metres, Celsius into Fahrenheit, or litres into gallons. Choose a measurement type to see only compatible units.
Unit converter
Runs on your deviceCheck the kind of measurement first
Units describe a quantity. Metres and feet measure length, while square metres and square feet measure area. A factor used for a length does not directly convert an area: a square has two dimensions. This converter separates measurement types so you cannot accidentally convert a length into an area. The weight category uses standard mass units for everyday comparisons.
A gallon is not always the same gallon
A US liquid gallon equals 3.785411784 litres. An imperial gallon equals 4.54609 litres. This difference matters when you compare container capacities. The menu labels the two versions explicitly. The cup option is a US customary cup of 236.5882365 millilitres; it is not the 250-millilitre metric cup used in some recipes. Check which convention your source uses.
Temperature needs an offset
Length, mass, volume, and area conversions multiply by a ratio. Celsius and Fahrenheit also have different zero points, so the calculation needs an offset: °F = °C × 9/5 + 32. Kelvin uses K = °C + 273.15. The converter rejects temperatures below absolute zero. Results are rounded for display to up to eight decimal places; small values can appear in scientific notation to preserve useful precision.
Worked examples
| From | To | Result |
|---|---|---|
| 1 kilometre | Metres | 1,000 |
| 25 °C | Fahrenheit | 77 °F |
| 1 US gallon | Litres | 3.785411784 |
Good questions.
Are US and imperial gallons interchangeable?
No. They have different volumes. Select the explicitly labelled gallon that matches your source.
Why can I not convert kilograms to litres?
Mass and volume describe different quantities. Converting between them requires the density of the material, which this tool does not assume.
Can I use a negative number?
Negative temperatures are supported above absolute zero. For length, mass, volume, and area, this everyday converter accepts non-negative measurements.
Updated 5 November 2026 · Methods & corrections