Unit Converter
One converter for the measurements you actually use: length, weight, temperature, volume, area, speed, time, and digital storage. Pick a category, choose your units, and the conversion happens instantly as you type — metric to imperial and back, with a one-tap swap.
1 Millimeter = 0.1 Centimeter
How to Use Unit Converter
Pick a category
Choose length, weight, volume, area, speed, time, data, or temperature.
Choose your units
Select the unit you're converting from and the unit you want.
Type your value
Enter a number and read the converted result instantly; tap swap to reverse direction.
About Unit Converter
How unit conversion works
Every unit in a category is defined by its ratio to a base unit — meters for length, grams for weight, liters for volume — so converting is two steps: multiply your value into the base unit, then divide by the target unit's factor. Five miles to kilometers is 5 × 1,609.344 m ÷ 1,000 m = 8.047 km. Temperature is the exception: Celsius, Fahrenheit, and Kelvin don't share a zero point, so the converter applies the proper affine formulas (°F = °C × 9/5 + 32; K = °C + 273.15) instead of simple ratios.
Exact definitions, not approximations
The conversion factors here follow the international definitions: an inch is exactly 25.4 mm, a pound exactly 453.59237 g, and a mile exactly 1,609.344 m — fixed by international agreement in 1959. Volume uses US customary measures (a US gallon is 3.785 liters; the UK imperial gallon is 4.546), and cooking units like cups and tablespoons are the US standard versions. Digital storage uses binary multiples (1 KB = 1,024 bytes), matching how operating systems report file sizes. Results are shown to eight significant digits.
Instant, private, and free
Conversions run entirely in your browser the moment you type — no upload, no server round-trip, no stored data, and it keeps working offline once the page is loaded. That makes it handy anywhere: doubling a European recipe in a US kitchen, checking a shipment's weight in pounds against a courier's kilogram limit, translating a 5K race into miles, or comparing an acreage listing to square meters. Use the swap button to flip the direction of any conversion with one click.
Common uses for Unit Converter
- Convert a European recipe's grams and milliliters into cups and ounces
- Translate kilometers to miles for a race distance or road trip
- Check luggage or shipping weight in kilograms against a limit quoted in pounds
- Compare property sizes across square feet, square meters, and acres
- Figure out how many gigabytes of storage a batch of files will need
Frequently Asked Questions
How accurate are the conversions?
Factors are the exact international definitions where they exist (1 in = 25.4 mm, 1 lb = 453.59237 g, 1 mi = 1,609.344 m), and results display up to eight significant digits. Any tiny discrepancy versus another tool usually comes from rounding display precision, not the underlying math.
Why is temperature converted differently from other units?
Length, weight, and volume scales all start at zero, so a simple ratio works. Temperature scales have different zero points — 0°C equals 32°F — so conversion needs both a multiply and a shift: °F = °C × 9/5 + 32, and Kelvin adds 273.15 to Celsius. A ratio alone would give wrong answers everywhere except at each scale's zero.
Are the volume units US or imperial (UK)?
US customary. A US gallon is 3.785 liters while a UK imperial gallon is 4.546 liters — about 20% larger — and pints, quarts, cups, and fluid ounces differ similarly. If you're following a British recipe or fuel-economy figure, keep that gap in mind.
Why does 1 kilobyte equal 1,024 bytes here and 1,000 elsewhere?
Two conventions coexist: binary (1 KB = 1,024 bytes), used by operating systems when reporting file and memory sizes, and decimal (1 kB = 1,000 bytes), used by drive manufacturers. This converter uses binary multiples, which is why a '1 TB' drive shows up as roughly 931 GB in your OS.
How do the time units define a month and a year?
Since calendar months vary from 28 to 31 days, the time category uses the common fixed conventions: a month is 30 days and a year is 365 days. For date-specific arithmetic — exact ages or day counts between real dates — use the Age Calculator, which works from the actual calendar.