Unit Converter

Convert length, weight and temperature between metric and imperial.

Metric ↔ Imperial, Without the Memorizing

This converter covers the four categories people need daily — length, weight, temperature and volume — across metric and US units. Values convert through exact standard factors (1 inch = 2.54 cm, 1 lb = 453.592 g), so results are precise, not rounded folklore.

The Conversions Worth Knowing by Heart

FromToQuick rule
InchesCentimeters× 2.54 exactly
PoundsKilograms≈ halve it, then −10 %
MilesKilometers× 1.6 (or × 8/5)
°F°C−32, then × 5/9
US gallonsLiters× 3.785

Temperature Is Different

Length, weight and volume scale by a factor; temperature also shifts its zero point. That's why 0 °C = 32 °F and the formula needs both a multiplication and an offset. Kelvin is Celsius shifted by 273.15 — the scale scientists use because it starts at absolute zero.

US vs. UK Units — A Warning

A US fluid ounce (29.57 ml) differs from a UK one (28.41 ml), and a US gallon (3.785 l) is far smaller than a UK gallon (4.546 l). This converter uses US customary volumes — relevant when reading British recipes or fuel economy figures.

Frequently Asked Questions

How many kg is 1 pound?
1 lb = 0.453592 kg. Quick estimate: halve the pounds and subtract 10 % — 150 lb → 75 − 7.5 ≈ 68 kg (exact: 68.04).
How do I convert Celsius to Fahrenheit?
°F = °C × 9/5 + 32. Handy anchors: 0 °C = 32 °F, 20 °C = 68 °F, 37 °C = 98.6 °F body temperature.
Are cups a reliable unit?
US recipe cups are 236.6 ml (legally rounded to 240 ml on nutrition labels). For baking accuracy, weight (grams) beats volume every time.
Why does 1 inch equal exactly 2.54 cm?
Since 1959 the inch has been defined as exactly 25.4 mm by international agreement — one of the few metric-imperial conversions with no rounding at all.