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Lbs to kg (lb to kg)

To convert lbs to kg (lb to kg): one pound is 0.45359237 kilograms, so 120 lb is 54.4311 kg.

Swap units: kg to lb

Notice: Not for calculating weight-based medication doses. Incorrect dosing can cause serious injury. Any such dose must be determined or confirmed by a pharmacist or physician.

In kilograms54.4311 kg

Conversion factor Exact by definition. The inch has been exactly 2.54 cm and the pound exactly 0.45359237 kg since the 1959 international yard and pound agreement, so these are not measurements that can drift.
1 pound = 0.45359237 kilograms
The other way
1 kilogram = 2.204622622 pounds
Working
120 x 0.45359237 = 54.4311
120 lb in every unit
54,431,084 mg 54,431 g 54.431 kg 0.054431 t 1,920 oz 120 lb 8.5714 st 0.06 ton 840,000 gr 35,000 dwt 1,750 oz t 145.83 lb t
pounds to kilograms
lbkg
10.453592
20.907185
52.26796
104.53592
2511.3398
5022.6796
10045.3592

How the Unit Converter works

One pound is exactly 0.45359237 kilograms. That is a definition rather than a measurement: the imperial and US customary units were fixed against metric ones by the 1959 international yard and pound agreement, so this factor does not drift and will not be revised.

Worked through: 120 lb x 0.45359237 = 54.4311 kg.

Going the other way, one kilogram is 2.204622622 pounds.

For mental arithmetic: Halve it and subtract 10%. 150 lb is 75 minus 7.5, so 67.5 kg; the exact answer is 68.0.

The direction an American needs for anything international: airline baggage allowances, gym equipment and shipping weights. Scientific and international records are kept in kilograms, so a weight read off a US scale in pounds is converted before it is recorded.

Precision is worth matching to the input. A measurement given as 1 lb carries one or two significant figures, and reporting its conversion to six implies a precision the original never had.

Unit Converter FAQ

How many kilograms are in a pound?

0.45359237. That is exact by definition: the 1959 international yard and pound agreement fixed it, and it does not change.

What is 120 lb in kilograms?

54.4311 kg. Multiply by 0.45359237: 120 lb x 0.45359237 = 54.4311 kg.

How do I convert kilograms back to pounds?

Divide by 0.45359237, or equivalently multiply by 2.2046226. One kilogram is 2.2046226 pounds. The two factors are reciprocals, so you only need to remember one of them.

Is there a quick way to do this in my head?

Halve it and subtract 10%. 150 lb is 75 minus 7.5, so 67.5 kg; the exact answer is 68.0. It is close enough for everyday use.

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