Free Online Unit Converter

Convert between units across 8 categories: temperature, length, weight, speed, data storage, time, area, and volume. Instant results in your browser.

📏 Unit Converter

Unit Conversion Made Simple

Whether you’re a developer calculating data storage requirements, a student converting physics problems, a traveler figuring out kilometers to miles, or a cook converting cups to milliliters — unit conversion is a daily task that’s easy to get wrong. This tool handles the math instantly so you can focus on what you’re actually working on.

Supported Categories

CategoryUnits includedCommon conversions
TemperatureCelsius, Fahrenheit, Kelvin°C to °F, °F to °C
Lengthmm, cm, m, km, in, ft, yd, mikm to miles, cm to inches
Weightmg, g, kg, oz, lb, tonkg to lbs, g to oz
Speedm/s, km/h, mph, knotskm/h to mph, m/s to km/h
Data StorageB, KB, MB, GB, TB, PBGB to TB, MB to GB
Timems, sec, min, hr, day, week, yearhours to minutes, days to hours
Areamm², cm², m², km², in², ft², acre, ham² to ft², acres to hectares
Volumeml, l, gal, cup, fl oz, m³liters to gallons, cups to ml

Tricky Conversions Explained

Temperature is non-linear

Unlike other units, temperature conversions use formulas, not simple multiplication. °F = (°C × 9/5) + 32. Kelvin = °C + 273.15. The tool handles these correctly.

Data storage: 1000 vs 1024

This tool uses decimal (SI) prefixes: 1 KB = 1,000 bytes, 1 MB = 1,000,000 bytes. Some systems use binary prefixes (KiB = 1,024 bytes). The difference matters when calculating disk space.

US vs Imperial gallons

A US gallon (3.785 liters) is different from an Imperial gallon (4.546 liters). This tool uses US gallons, which are the global standard in most contexts.

Nautical vs statute miles

A nautical mile (1.852 km) is used in maritime and aviation, while a statute mile (1.609 km) is the “normal” mile used in everyday life. Speed in knots uses nautical miles per hour.

Frequently Asked Questions

How accurate are the conversions?

The tool uses JavaScript’s double-precision floating-point arithmetic, which provides about 15–17 significant digits of precision. This is more than sufficient for any practical conversion. Results are rounded to a reasonable number of decimal places for readability.

Can I convert between categories?

No — you can only convert between units within the same category. Converting meters to kilograms doesn’t make physical sense, as they measure different quantities (length vs mass).

Why is my data storage conversion different from what my OS shows?

Operating systems often mix decimal and binary prefixes. A hard drive advertised as “500 GB” uses decimal (500,000,000,000 bytes), but Windows displays it using binary math, showing approximately 465 GiB. This tool uses consistent decimal (SI) prefixes.

Is the conversion done server-side?

No. All calculations happen in your browser using JavaScript. No data is sent to any server.

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