Unit Converter
Convert between units of length, weight, temperature, area, volume, speed, time, and data storage instantly.
Unit Converter is a fast, browser-based tool that converts between common units across eight categories. Select a category, enter a value, choose the source and target units, and the result appears instantly. You can also type into the result field to convert in reverse. All calculations run in your browser — nothing is sent to a server.
Tool interface
The interface has three parts:
- Category — choose one of the eight conversion categories from the dropdown
- From / To — enter a value in the left field and select units in both dropdowns; typing in either field converts in the other direction automatically
- Swap — the arrow button swaps the from and to units while keeping the current value
- Common conversions — quick-select buttons appear below to load frequently used unit pairs in one click
Categories and units
Length
Millimetre, centimetre, metre, kilometre, inch, foot, yard, mile, nautical mile
Weight / Mass
Milligram, gram, kilogram, metric ton, ounce, pound, stone
Temperature
Celsius (°C), Fahrenheit (°F), Kelvin (K)
Area
Square millimetre, square centimetre, square metre, square kilometre, square inch, square foot, square yard, acre, hectare
Volume
Millilitre, litre, cubic metre, teaspoon (US), tablespoon (US), fluid ounce (US), cup (US), pint (US), quart (US), gallon (US)
Speed
Metre/second, kilometre/hour, mile/hour, foot/second, knot
Time
Millisecond, second, minute, hour, day, week, month (average), year (average)
Data Storage
Bit, byte, kilobyte, megabyte, gigabyte, terabyte, kibibyte, mebibyte, gibibyte, tebibyte
Conversion method
All non-temperature units are converted through a base unit:
result = input × (from_factor / to_factor)Each unit stores a factor representing how many base units it equals (for example, 1 km = 1000 m, so the kilometre factor is 1000).
Temperature uses offset formulas: °F = °C × 9/5 + 32 and K = °C + 273.15.
Common use cases
- Travel — convert km/h to mph or temperatures between Celsius and Fahrenheit
- Cooking — convert cups, tablespoons, and fluid ounces to millilitres
- Engineering — convert between imperial and metric lengths or areas
- Storage — convert between megabytes, gigabytes, and terabytes
- Fitness — convert pounds to kilograms or miles to kilometres
FAQ
Can I convert in both directions?
Yes. Typing in either the From or To field converts in the opposite direction automatically. You can also use the swap button to reverse the selected units.
How accurate are the conversions?
The tool uses up to 10 significant digits in its output. Factors are stored as precise decimal values. For most everyday purposes the result is fully accurate. Very large or very small numbers follow standard IEEE 754 double-precision behaviour.
Why does the acre or mile not appear in the Area quick buttons?
The quick-select buttons show the four most commonly needed conversions for each category. All units are still available in the From and To dropdowns.
What does KB vs KiB mean?
KB (kilobyte) and KiB (kibibyte) are both shown in the Data Storage category. In this calculator both are treated as 1024 bytes (binary), which is the standard meaning used in operating systems and file storage contexts.
Is temperature conversion linear like the others?
No. Temperature is the only category that uses an offset formula rather than a simple multiplication factor. The tool handles this automatically — you do not need to adjust anything.