Free online calculator
Unit converter
Length, weight, temperature, and more.
Unit converter
12 categories — type in any field to convert instantly across all units.
How to use this calculator
- 1
Pick a category
Click one of the 12 tabs across the top to select the type of measurement.
- 2
Type a value
Enter a number in any unit row — the field accepts decimal values.
- 3
Read the conversions
All other rows in the category update immediately to show the equivalent value.
- 4
Switch category
Click a different tab to convert a new type of measurement.
Formula
Linear units (length, weight, volume, speed): every unit stores a factor to the base unit. Converting A → B = value × factorA ÷ factorB.
Temperature (affine): convert to °C first, then to the target. °F → °C = (v − 32) × 5/9. K → °C = v − 273.15.
Worked example
5 feet to other lengths:
5 ft × 0.3048 m/ft = 1.524 m. → 152.4 cm. → 1524 mm. → 60 in. → 1.6667 yd. → 0.000947 mi.
100 °F to °C and K:
(100 − 32) × 5/9 = 37.78 °C. → 37.78 + 273.15 = 310.93 K.
FAQ
Does it handle US vs UK units? +
Volume uses US gallons, US fluid ounces, and US cups. There are no UK imperial volume units. For fuel efficiency between US and UK MPG, use the dedicated fuel efficiency calculator.
How accurate are the conversions? +
All conversion factors use SI-defined exact values where available: 1 inch = 0.0254 m, 1 lb = 0.45359237 kg, 1 US gallon = 3.785411784 L. Results are shown to up to 10 significant figures.
Why is temperature handled differently from other categories? +
Temperature uses affine (offset) conversion, not a simple multiplication. Converting 0 °C to Kelvin gives 273.15, not 0. Each temperature unit has its own to-base and from-base function to handle this correctly.
What is the difference between KB (kilobyte) and KiB (kibibyte)? +
KB (kilobyte) uses decimal powers: 1 KB = 1000 bytes. KiB (kibibyte) uses binary powers: 1 KiB = 1024 bytes. Hard drive manufacturers typically use decimal; operating systems often report sizes in binary. Both are included in the Data tab.
What month and year lengths are used in the Time category? +
Month uses an average of 30.4375 days (365.25 ÷ 12). Year uses 365.25 days to account for leap years. These are calendar averages, not exact astronomical values.
Can I convert more than one value at a time? +
Each category tab has one active value. For multiple independent conversions, open the page in separate browser tabs.
About this calculator
This unit converter covers 12 categories: length, weight, temperature, volume, speed, data, time, pressure, force, energy, power, and angle. Type any value into any row and all other units in the same category update instantly — no direction or convert button needed.
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