Unit Converter

From	To	Formula
mm	cm	1 mm = 0.1 cm
mm	m	1 mm = 0.001 m
cm	mm	1 cm = 10 mm
cm	m	1 cm = 0.01 m
m	mm	1 m = 1,000 mm
m	cm	1 m = 100 cm
km	mm	1 km = 1,000,000 mm
km	cm	1 km = 100,000 cm
in	mm	1 in = 25.4 mm
in	cm	1 in = 2.54 cm
ft	mm	1 ft = 304.8 mm
ft	cm	1 ft = 30.48 cm

You’re reading API documentation that specifies a file size limit as 10 MiB but your upload form shows MB. Or a hardware spec lists dimensions in millimeters and you need inches for a US supplier. Or a recipe calls for 350°F and your oven uses Celsius. Instead of searching for each conversion formula separately, this tool handles all common unit categories in one place.

Why This Tool

Online unit converters are everywhere, but most are cluttered with ads and require page reloads between categories. This tool covers 7 unit categories — length, weight/mass, temperature, volume, area, speed, and data storage — in a single clean interface. Type a value, select units, and see the result instantly. No ads, no tracking, runs entirely in your browser.

Supported Categories

Length

Millimeter, centimeter, meter, kilometer, inch, foot, yard, mile. Core conversions: 1 inch = 25.4 mm, 1 mile = 1.609344 km, 1 foot = 30.48 cm.

Weight / Mass

Milligram, gram, kilogram, metric ton, ounce, pound, stone. Core: 1 kg = 2.20462 lb, 1 oz = 28.3495 g.

Temperature

Celsius, Fahrenheit, Kelvin.

°F = °C × 9/5 + 32
K = °C + 273.15
°C = (°F − 32) × 5/9

Volume

Milliliter, liter, US gallon, US quart, US pint, US fluid ounce, cubic meter. Core: 1 US gallon = 3.78541 liters.

Area

Square millimeter, square centimeter, square meter, hectare, square kilometer, square inch, square foot, acre, square mile.

Speed

Meters per second, kilometers per hour, miles per hour, knots, feet per second.

Data Storage

Bit, byte, kilobyte (KB), megabyte (MB), gigabyte (GB), terabyte (TB), kibibyte (KiB), mebibyte (MiB), gibibyte (GiB), tebibyte (TiB).

Important distinction: 1 KB = 1000 bytes (SI/decimal), 1 KiB = 1024 bytes (binary/IEC). This tool handles both correctly.

The Metric vs Imperial Question

The metric system (SI) is used by most of the world and all scientific work. The imperial/US customary system is used primarily in the United States. Developers frequently encounter both — CSS uses pixels (neither system), APIs may specify limits in either, and international projects mix units constantly.

Data Storage: KB vs KiB

This distinction causes real confusion:

Unit	Bytes	Standard
1 KB (kilobyte)	1,000	SI (decimal)
1 KiB (kibibyte)	1,024	IEC (binary)
1 MB (megabyte)	1,000,000	SI
1 MiB (mebibyte)	1,048,576	IEC
1 GB (gigabyte)	1,000,000,000	SI
1 GiB (gibibyte)	1,073,741,824	IEC

Operating systems, file managers, and cloud providers use these inconsistently. A “1 GB” file may be 1,000,000,000 or 1,073,741,824 bytes depending on the context.

Frequently Asked Questions

How do I convert Fahrenheit to Celsius? Subtract 32, then multiply by 5/9. For example: 72°F → (72 − 32) × 5/9 = 22.2°C. This tool does the math instantly for any temperature value.

What is the difference between KB and KiB? KB (kilobyte) = 1,000 bytes using the SI decimal standard. KiB (kibibyte) = 1,024 bytes using the IEC binary standard. The difference grows with scale: 1 TB vs 1 TiB differs by about 10%.

Does this tool handle negative values? Yes. Negative values are valid for temperature conversions (e.g., −40°C = −40°F) and are handled correctly. For other categories, negative values are mathematically converted but may not have physical meaning.

Are the conversions exact? Length, weight, and volume conversions use the internationally defined exact factors (e.g., 1 inch = exactly 25.4 mm). Temperature conversions are mathematically exact. Results are displayed with appropriate precision.

Does this tool work offline? Yes. All conversion formulas run in JavaScript in your browser. No network requests are made.

All Conversions