Kilograms to Pounds

Kilograms and pounds

The kilogram is the SI base unit of mass, defined since 2019 by fixing the Planck constant. Body weight, groceries, luggage allowances and most product weights outside the US are given in kilograms.

The avoirdupois pound is exactly 0.45359237 kilograms (1959 agreement) and contains 16 ounces. Body weight, food and product weights in the US, and body weight alongside stone in the UK, use pounds.

Worked example

Convert 70 kg: 70 × 2.204622622 = 154.3235835, so 70 kilograms is 154.3235835 pounds. Likewise 20 kg = 44.09245244 lb.

Estimating in your head

Multiply by 2.2 for a quick figure; it is off by about 0.2%. For 70 kg that gives 154 lb, against 154.324 exactly.

Going the other way

To convert pounds to kilograms, divide by 2.204622622 (or multiply by 0.45359237). The swap button between the boxes opens that page.

lb = kg × 2.204622622

1 kg = 1 kg and 1 lb = 0.45359237 kg, both by definition, so the factor is their ratio: 2.204622622 (rounded here; the page uses the full value). Results drop binary floating-point noise beyond 15 significant digits and display at the precision you choose (6 significant figures by default). Copy result copies the full value.