Unit Converter - Convert Between Measurements

How it works:

Convert between common units for length, weight, volume, temperature, speed, and more. Real-time conversion as you type.

Conversion Type:

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Convert a value from one unit to another — length, weight, temperature and more. Enter a number, pick the units, and read off the result. Handy for recipes, travel, shipping, DIY and homework.

How unit conversion works

Most conversions are simple multiplication by a conversion factor — a fixed ratio between two units. For example, 1 mile = 1.609 km, so any distance in miles times 1.609 gives kilometres.

Temperature is the exception. Because Celsius and Fahrenheit have different zero points, you can't just multiply — you apply a formula that both scales and shifts: °F = °C × 9/5 + 32. That "+ 32" offset is why 0°C isn't 0°F.

When and why you'd use it

Cooking — convert a recipe's grams to ounces, or Celsius oven temps to Fahrenheit.
Travel — miles to kilometres, and reading the local weather in the other temperature scale.
Shipping & DIY — weights for postage, lengths for materials.

Worked examples

10 km → 6.21 miles (divide by 1.609, or multiply by 0.621).

100 °C → 212 °F — using °F = 100 × 9/5 + 32. Water boils at both, which is a good sanity check.

5 kg → 11.02 lb (× 2.2046).

60 mph → 96.6 km/h (× 1.609) — the same factor as miles to kilometres, since it's distance covered in the same amount of time.

Quick reference: common conversions

1 mile = 1.609 km · 1 km = 0.621 miles
1 inch = 2.54 cm (exact) · 1 foot = 30.48 cm
1 kg = 2.205 lb · 1 lb = 0.454 kg
1 US gallon = 3.785 L · 1 imperial gallon = 4.546 L
1 mph = 1.609 km/h · °F = °C × 9/5 + 32

Some factors are exact by definition — an inch is defined as precisely 2.54 cm — while others, like pounds to kilograms, are rounded for everyday use.

Frequently asked questions

Why isn't temperature just a multiplication?

Because the scales start at different points. Celsius sets 0 at water's freezing point; Fahrenheit doesn't. So converting needs both a scaling factor and an offset, not a single ratio.

Are US and imperial units the same?

Not always — a US gallon (~3.785 L) is smaller than an imperial gallon (~4.546 L), and fluid ounces differ too. Make sure you're using the system your recipe or spec intends.

How precise are the results?

Results are rounded to a few decimals for readability, using standard conversion factors. For scientific or engineering work, keep more decimal places.

Can it convert currency?

No — this handles fixed physical units. Currency rates change constantly and need live data.

Mind the system and the rounding. US customary and imperial units share names but differ in size (gallons, ounces). And rounding that's fine for cooking may not be precise enough for scientific use.