How this calculator works
The avoirdupois pound is exactly 0.45359237 kg by the 1959 international yard and pound agreement, so converting pounds to kilograms is an exact multiplication. Results are rounded only for display.
Formula
kilograms = pounds × 0.45359237.
Worked example
180 lb to kilograms: 180 × 0.45359237 = 81.6466 kg.
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Frequently asked questions
Why multiply rather than divide going this direction?
A pound is smaller than a kilogram, so the same mass is a smaller number of kilograms. Multiplying by the exact 0.45359237 kg definition does that.
Does this factor work for stone too?
A stone is exactly 14 lb, so convert stone to pounds first, or use the general weight and mass converter page.
Can I enter a value in ounces?
Yes. Choose ounces as the starting unit and kilograms as the result; the converter uses the same exact mass factors for every unit pair.