Convert between 100+ units across length, weight, temperature, area, volume, speed, data, and time.
Formula: 1 mm = 0.1 cm
Millimeter
1
mm
Centimeter
0.1
cm
Meter
0.001
m
Kilometer
0.000001
km
Inch
0.0393700787402
in
Foot
0.00328083989501
ft
Yard
0.00109361329834
yd
Mile
6.21371192237e-7
mi
Nautical Mile
5.39956803456e-7
nmi
The Unit Converter turns a value from one unit of measurement into another across everyday and technical categories: length (mm, cm, m, km, inch, foot, yard, mile), weight and mass (mg, g, kg, tonne, ounce, pound), temperature (Celsius, Fahrenheit, Kelvin), speed (m/s, km/h, mph, knots), and digital data (bit, byte, KB, MB, GB, TB). You pick a category, enter a number, choose the source and target units, and the converted result appears instantly in your browser.
It is built for students checking homework, engineers and DevOps folks translating data sizes and transfer speeds, cooks and travelers dealing with metric-versus-imperial values, and anyone who needs a quick, reliable conversion without installing an app or hunting through search results.
Most conversions are ratio-based: each unit is defined relative to a base unit for its category, and the tool converts by dividing into the base and multiplying out to the target. For length the base is the meter, so 1 mile equals 1609.344 meters and 1 inch equals 0.0254 meters; converting 5 miles to kilometers means 5 x 1609.344 = 8046.72 m = 8.04672 km. Weight uses the kilogram as its base (1 pound = 0.45359237 kg), and speed uses meters per second (1 km/h = 0.277778 m/s, 1 knot = 0.514444 m/s).
Temperature is the exception because the scales do not share a zero point, so it uses formulas instead of a single factor: Fahrenheit to Celsius is (F - 32) x 5/9, Celsius to Fahrenheit is (C x 9/5) + 32, and Kelvin is C + 273.15. Data conversions default to binary prefixes where 1 KB = 1024 bytes and 1 MB = 1024 KB, which is why a 1 GB file reads as roughly 1.07 billion bytes rather than exactly one billion.
Yes, it is completely free with no sign-up required. All calculations run locally in your browser, so the values you enter are never uploaded to a server or stored anywhere.
Choose the Temperature category, enter your Fahrenheit value, set the from unit to Fahrenheit and the to unit to Celsius. The tool applies (F - 32) x 5/9, so 98.6 F converts to 37 C.
The digital data category uses binary prefixes by default, where 1 KB = 1024 bytes, 1 MB = 1024 KB, and so on. This matches how operating systems typically report file and storage sizes.
Yes. You can freely mix systems, for example centimeters to inches, kilograms to pounds, or kilometers per hour to miles per hour, within any single category.
Conversions only work between units of the same physical quantity. Weight and length measure different things, so the tool keeps each category separate to prevent meaningless results.
Conversions use internationally defined exact factors (for example 1 inch = 0.0254 m and 1 pound = 0.45359237 kg), so results are precise. Displayed values may be rounded for readability, but the underlying math is exact.
You need a connection to load the page the first time, but once loaded the conversions compute entirely on your device without further network requests.