What Is the Pounds to Kilograms Converter?
This tool converts a weight given in pounds (lb) into kilograms (kg), the SI base unit of mass. The pound is part of the imperial and US customary systems, while the kilogram is used almost everywhere else and across science. By international agreement, one pound is defined as exactly 0.45359237 kilograms, so the conversion is precise — not an approximation.
How to Use It
Enter the weight in pounds and the calculator instantly returns the equivalent in kilograms (and grams). It works for any positive value: body weight, parcel weight, gym plates, or recipe ingredients. Decimal values such as 12.5 lb are fully supported.
The Formula Explained
The conversion uses a single multiplication:
$$\text{kg} = \text{lb} \times 0.45359237$$
Because the factor is an exact definition, the result is as accurate as your input. To go the other way (kg to lb), divide by the same factor, or multiply by about \(2.2046226\).
Worked Example
Suppose you weigh 150 pounds. Multiply: $$150 \times 0.45359237 = 68.0388555 \text{ kg}.$$ So 150 lb is roughly 68.04 kg. For a quick mental estimate, dividing pounds by 2.2 gives a close approximation (\(150 \div 2.2 \approx 68.2\)).
FAQ
Is 1 pound exactly 0.45359237 kg? Yes. This value was fixed by the international yard and pound agreement of 1959 and is exact.
How many pounds are in a kilogram? One kilogram equals about 2.2046226 pounds (\(1 \div 0.45359237\)).
Does this work for ounces? Convert ounces to pounds first (16 oz = 1 lb), then use this tool. For example 8 oz = 0.5 lb ≈ 0.227 kg.
