Unit Converter
Convert length, weight, volume, and temperature. All major units in one place.
Recipes in grams when your scale reads ounces, a height given in centimetres when you think in feet, a road sign in kilometres when your instinct is miles — unit mismatches cause small daily frictions and occasionally expensive mistakes. This converter handles the four categories people need most: length, weight, volume, and temperature, all in one place, so you can move between metric and imperial without hunting for the right formula.
It is built for cooks, travelers, students, DIYers, and anyone who works across the metric–imperial divide. Rather than memorizing dozens of conversion factors, you pick the quantity, enter a value, and read the equivalent instantly. The page also explains the logic behind each conversion, because understanding why a kilogram is about 2.2 pounds — rather than just trusting a number — helps you estimate on the fly and spot when a result looks wrong.
Plug in some numbers —
we'll crunch.
How to use
- 1Select the conversion type: length, weight, volume, or temperature.
- 2Enter the value you want to convert.
- 3Choose the source unit.
- 4Choose the target unit.
- 5Click Calculate to see the result.
How it works
Most unit conversions are simple multiplication by a fixed factor. Length, weight, and volume all work this way: 1 inch = 2.54 cm, 1 kilogram = 2.20462 pounds, 1 US gallon = 3.78541 litres. To convert, you multiply by the factor (or divide to go the other way). Chaining factors lets you bridge any two units in the same category, which is exactly what this tool does behind the scenes.
Temperature is the exception, because the Celsius and Fahrenheit scales have different zero points as well as different step sizes. Converting requires both a multiplication and an addition: °F = °C × 9/5 + 32, and °C = (°F − 32) × 5/9. Kelvin shares Celsius's step size but starts at absolute zero, so K = °C + 273.15. This offset is why you cannot simply scale temperatures the way you scale lengths.
Worked examples
Converting a recipe
A recipe calls for 250 grams of flour but your scale only reads in ounces.
- 1 ounce = 28.35 grams.
- Divide: 250 ÷ 28.35 ≈ 8.8 ounces.
You need about 8.8 ounces of flour. For weight-based baking, measuring in grams is actually more precise — which is why serious bakers often switch their scales to metric.
Temperature for a recipe or trip
An oven recipe says 180°C and your oven is marked in Fahrenheit.
- Apply °F = °C × 9/5 + 32.
- 180 × 9/5 = 324, then 324 + 32 = 356°F.
Set the oven to about 356°F (most dials round to 350°F). Notice you can't just multiply 180 by a single factor — the +32 offset is essential, which is what makes temperature different from length or weight.
Tips & common mistakes
Watch out for the two kinds of 'ounce' and 'gallon'. A fluid ounce measures volume while a dry ounce measures weight — they are not interchangeable. Likewise, a US gallon (3.79 L) is smaller than an imperial UK gallon (4.55 L), and US and UK pints differ too. Mixing these up is a classic source of recipe and fuel-economy errors.
Keep a few rough conversions in your head for sanity checks: a kilogram is a bit over two pounds, a metre is just over three feet, a litre is close to a US quart, and 100 km is about 62 miles. If a converted result is wildly different from your mental estimate, you have probably picked the wrong unit or category.
For temperature, remember the offset means the scales cross at −40° (−40°C equals −40°F) and that body temperature, 37°C, is 98.6°F. Rounding is usually fine for cooking and travel, but for scientific or medical work, carry the full decimals. This converter is a practical everyday tool; for engineering or laboratory precision, verify against an authoritative reference.
Frequently asked questions
Last reviewed: June 2026
About this calculator
Convert length, weight, volume, and temperature. All major units in one place.