Unit Converter

How to Use the Unit Converter

1. Select a category tab — Length, Weight, Temperature, or any of the eight options.
2. Enter a value in the Value field.
3. Choose your starting unit in From and your target unit in To.
4. The result updates immediately. Use ⇅ Swap to reverse the conversion.
5. Scroll down the result card to see real-world scale comparisons for the converted value.

How Unit Conversion Works

Most unit conversions use a single multiplier: multiply the input by a conversion factor to get the output. One inch equals 2.54 cm exactly, so multiply inches by 2.54 to get centimetres, or divide by 2.54 to go the other way.

Temperature is the exception — it requires both multiplication and addition because the zero points differ between scales. Celsius, Fahrenheit, and Kelvin don't share a common zero point.

Temperature Conversion Formulas

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

Metric vs Imperial

Metric (SI) units use powers of 10. Prefixes — kilo (×1,000), centi (÷100), milli (÷1,000) — apply consistently across length, mass, and volume. Most of the world uses metric exclusively.

Imperial units (inches, feet, miles, pounds, gallons) are used primarily in the United States. Their ratios are arbitrary: 12 inches per foot, 3 feet per yard, 1,760 yards per mile. The UK uses a mix of both systems depending on context.

Common Conversion Mistakes

Fluid ounces vs weight ounces. A fluid ounce (fl oz) measures volume; a weight ounce (oz) measures mass. Water makes them nearly equal, but other substances differ. Recipe conversions must distinguish them.

US pints vs UK pints. A US pint is 473 mL. A UK pint is 568 mL — about 20% larger. A US pint of beer is meaningfully smaller than a UK one.

Short tons, metric tonnes, long tons. Short ton (US) = 907 kg. Metric tonne = 1,000 kg. Long ton (UK) = 1,016 kg. Check which is meant in any shipping or commodity context.

Mass vs weight. Mass (kilograms) is the amount of matter. Weight is gravitational force (newtons). On Earth they're proportional, so converters treat them as equivalent — but the distinction matters in physics and engineering.

Digital Storage Units

Data storage uses two parallel prefix systems. SI prefixes mean powers of 10: 1 KB = 1,000 bytes, 1 MB = 1,000,000 bytes. Binary prefixes mean powers of 2: 1 KiB = 1,024 bytes, 1 MiB = 1,048,576 bytes.

Hard drive manufacturers use decimal prefixes (more bytes on the label). Operating systems use binary calculations (fewer bytes shown). A drive advertised as 1 TB holds 10¹² bytes; the OS reports roughly 931 GiB because 10¹² ÷ 2³⁰ ≈ 931. All the data is there — the two systems just define prefixes differently.

Real-World Scale Anchors

Large measurements become easier to understand with reference points. One metre is roughly the distance from the floor to a door handle. One kilogram is close to a litre of water. One litre is four standard cups. One hectare is roughly 1.5 football pitches.

For speed: walking is about 5 km/h, highway driving is 110–130 km/h, a commercial aircraft cruises at around 900 km/h. For digital storage: a typical smartphone photo is 3–5 MB, a 4K movie is 60–100 GB, a full laptop drive is 500 GB to 2 TB.