Home › Cooking Converters › Pounds to Kilograms Converter
Convert avoirdupois pounds and additional ounces into kilograms, or convert kilograms back into pounds and ounces. The calculator is intended for food packages, recipe quantities, kitchen scales and general mass conversion. It treats pounds and ounces as units of mass, not fluid ounces.
Pounds to kilograms converter
Results are estimates based on the values you enter. Nothing you type is sent to or stored on our servers.
Conversion equations
The international avoirdupois pound is defined as exactly 0.45359237 kg. One avoirdupois ounce is exactly 0.028349523125 kg, and 16 ounces make one pound. For pounds plus extra ounces, the engine calculates: kg = (pounds × 0.45359237) + (extra ounces × 0.028349523125). For the reverse direction, pounds = kilograms ÷ 0.45359237.
The extra-ounces field is used only in the pounds-to-kilograms direction. When converting kilograms to pounds, enter the kilogram amount and select the reverse direction; the calculator reports decimal pounds and a pounds-and-ounces equivalent.
Verified examples
Example 1: 5 lb 8 oz equals 5 × 0.45359237 + 8 × 0.028349523125 = 2.494758 kg, displayed as approximately 2.495 kg. This is a useful check because 8 oz is exactly half a pound.
Example 2: 2.5 kg ÷ 0.45359237 = 5.51156 lb. The equivalent mixed quantity is approximately 5 lb 8.2 oz. Small display differences come from rounding, not from a different conversion factor.
How to use the calculator
- For pounds to kilograms, enter the whole or decimal pounds. Add any remaining ounces in the optional extra-ounces field.
- Select Pounds to kilograms and calculate. The result includes kilograms and an approximate gram equivalent.
- For kilograms to pounds, enter the kilogram value, select Kilograms to pounds and calculate. Read both decimal pounds and the mixed pounds-and-ounces result.
Units, precision and limitations
A pound is a mass unit. A US fluid ounce is a volume unit and cannot be converted to kilograms without knowing the liquid density. Do not use this converter for fluid ounces, cups or milliliters. For a recipe, keep the same mass basis before and after scaling; converting a liquid volume to mass is a separate density problem.
The conversion constants are exact by definition, but a kitchen scale, package label or rounded input may be less precise. The calculator displays three decimal places for kilograms and two for decimal pounds, so the final digits should not be interpreted as measurement accuracy.
Frequently asked questions
How many kilograms are in one pound?
One international avoirdupois pound is exactly 0.45359237 kg, or about 453.592 g.
How many ounces are in a pound?
There are 16 avoirdupois ounces in one pound. Eight ounces are half a pound.
Are pounds and fluid ounces interchangeable?
No. Pounds and ounces measure mass; fluid ounces measure volume. A density is needed to convert between volume and mass.
Related tools and reference
For ounce-to-gram conversion, use the Ounces to Grams Converter. For ingredient volume-to-mass estimates, see the Cups to Grams Converter. The international pound definition is documented in the NIST customary-to-metric conversion guide.