Unit Converter

Convert any measurement in seconds

Whether you're following a recipe, planning a trip, doing homework, or working on a technical project, this free unit converter makes switching between measurement systems effortless. Convert centimeters to inches, kilograms to pounds, Celsius to Fahrenheit, liters to gallons and much more — all without leaving your browser.

The converter supports both metric and imperial units across eight categories: length, weight and mass, temperature, volume, area, speed, time and digital data. Type a value into either field and the result appears instantly, so you can convert in either direction and double-check your numbers with the quick-conversion list.

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How unit conversion actually works

Most units in this tool are converted with a multiplier to a base unit. Length uses the metre, weight uses the kilogram, volume uses the litre, and so on. Every other unit stores how many base units it equals — an inch is 0.0254 m, a pound is 0.45359237 kg.

To convert from unit A to unit B:

result = value × (factor A ÷ factor B)

You multiply by A's factor to reach the base unit, then divide by B's factor to leave the base unit. Converting 5 feet to inches: 5 × 0.3048 ÷ 0.0254 = 60 inches. The tool does this instantly whichever direction you type.

Temperature is different

Celsius, Fahrenheit and Kelvin are not simple multiples of each other — they have offsets. You cannot convert °C to °F by multiplying alone:

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

That is why temperature is handled separately in the code while length and weight share the same factor logic.

Worked examples

Common mistakes to watch for

• US gallon vs imperial gallon. A US gallon is 3.785 litres; an imperial (UK) gallon is 4.546 litres — about 20% larger. Recipe and fuel-economy confusion often comes from mixing them up. This tool labels them separately.
• Metric ton vs US ton. A metric tonne is 1,000 kg. A US short ton is 2,000 lb (907 kg). They differ by roughly 10% — enough to matter in shipping and agriculture.
• Treating Fahrenheit as a ratio scale. "Twice as hot" in Fahrenheit is meaningless because zero is arbitrary. 40 °F is not "twice as warm" as 20 °F. Always convert temperature differences with the proper formula, not by multiplying.
• Confusing weight and mass. In everyday speech "weight" and "mass" blur together. Strictly, kilograms measure mass and pounds-force measure weight, but for practical conversions on Earth the numbers match what scales show.

When to use this tool

Reach for the unit converter when you are translating physical measurements — recipe volumes, road-trip distances, clothing sizes, screen dimensions, data storage, running pace. Pick the category first, then the two units; type in either field.

Use the Currency Converter for money between countries — it applies live exchange rates, which is completely different math. Use the BMI Calculator when you specifically want a body mass index from height and weight, not a raw kg-to-lb conversion. Use the Time Zone Converter when the hard part is clock time across regions, not miles versus kilometres.

Because everything runs on your device, there's nothing to install and nothing is uploaded. Your inputs stay completely private, and the tool works even when you're offline. This is one of many free browser tools on Uzetool — explore more tools as we add them.