Convert lbs to kg exactly, from pounds or stone and pounds, or switch to kg to lbs.
| Pounds | Kilograms |
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1 lb is exactly 0.45359237 kg by international definition, so results are exact before rounding. Body weight results are for conversion only, not health advice.
This lbs to kg converter changes a weight in pounds into kilograms for anyone moving between US or older British labels and the metric figures used across Europe and most of the world. Enter plain pounds or stone and pounds, and you get kilograms, grams, pounds and ounces and a quick mental estimate, all based on the exact international avoirdupois pound of 0.45359237 kg. A switch flips it to kg to lbs when you start from a metric figure.
Quick answer: To convert lbs to kg, multiply the pounds by 0.45359237, or divide by 2.2046 for nearly the same answer. One pound is 0.4536 kg, so 150 lbs is 68.04 kg and 200 lbs is 90.72 kg. For a fast estimate, halve the pounds and take away 10% of that half.
In This Guide
What Is a Pounds to Kilograms Conversion?
A pounds to kilograms conversion changes a mass measured in the imperial pound (lb) into the metric kilogram (kg) by multiplying by 0.45359237. The abbreviation "lb" comes from the Roman libra, which is why the unit is written lb or lbs even though the word is pound.
The formula is kilograms = pounds × 0.45359237, and the reverse is kilograms ÷ 0.45359237, which is the same as multiplying by about 2.20462. Grams are kilograms × 1,000. In the UK, people often weigh themselves in stone: 1 stone is 14 lb, or 6.35 kg.
How to Use the LBS to KG Converter
Step 1: Choose the Direction
Keep the toggle on lbs to kg for this conversion, or switch to kg to lbs to go the other way. The current weight carries across, so you can check both directions without retyping.
Step 2: Enter the Weight
Type the weight in pounds, with decimals if needed, or choose Stone + lb to enter a British body weight such as 10 st 10 lb. Switching between the two modes keeps the same weight.
Step 3: Pick the Decimal Places
One decimal place is enough for body weight and luggage. Use 2 or 3 for recipes, postage and lab work, where a few grams can matter.
Step 4: Read the Results
The big figure is the weight in kilograms, with the full sum written underneath. You also see grams, stone and pounds, pounds and ounces and the quick ÷ 2.2 estimate, so you can judge how close a mental answer would be. If you want the reverse page with its own table, the kg to lbs converter starts from kilograms, and its examples cover gym plates and baggage limits.
How Many Kilograms Are in a Pound?
There are exactly 0.45359237 kilograms in one pound, which is 453.59 grams. The figure was fixed in 1959 by the international yard and pound agreement, so pounds to kg conversions give the same answer in the US, the UK, Canada and Australia.
LBS to KG Conversion Table
| Pounds (lb) | Kilograms (kg) | Stone and pounds |
|---|---|---|
| 1 lb | 0.45 kg | 0 st 1 lb |
| 5 lb | 2.27 kg | 0 st 5 lb |
| 10 lb | 4.54 kg | 0 st 10 lb |
| 25 lb | 11.34 kg | 1 st 11 lb |
| 50 lb | 22.68 kg | 3 st 8 lb |
| 100 lb | 45.36 kg | 7 st 2 lb |
| 150 lb | 68.04 kg | 10 st 10 lb |
| 180 lb | 81.65 kg | 12 st 12 lb |
| 200 lb | 90.72 kg | 14 st 4 lb |
| 250 lb | 113.4 kg | 17 st 12 lb |
Kilogram figures are rounded to 2 decimal places. The stone column helps UK readers, who often know their body weight in stone rather than pounds.
How Do I Convert Pounds to KG in My Head?
To convert pounds to kg in your head, halve the number of pounds, then subtract 10% of that half. For 180 lb, half is 90 and 10% of 90 is 9, giving 81 kg against an exact answer of 81.65 kg, so the shortcut lands within about 1%.
Worked example: Daniel is flying home from Chicago and his bathroom scale at the hotel says his suitcase weighs 50 lbs. His airline allows 23 kg in the hold. Using the converter, 50 × 0.45359237 = 22.68 kg, so the case is 0.32 kg under the limit. Dividing by 2.2 would give 22.73 kg, close enough here, but a 51 lb case would be 23.13 kg and over.
Weight is only half of the baggage rules. Before packing, the luggage size checker confirms whether the case dimensions also fit the airline's limits, so Daniel avoids a surprise fee at the desk.
Why Do UK Labels Show Kilograms but People Use Pounds?
UK labels show kilograms because goods sold in England, Scotland and Wales must be weighed in metric units, while pounds survive as a familiar everyday unit. The GOV.UK weights and measures rules allow an imperial figure alongside the metric one, as long as it does not stand out more, which is why packs may show both.
In the US, pounds remain the main unit for body weight, food and freight, so recipes, gym equipment and shipping quotes often need converting. For British body weights in stone, the stone to kg converter works from stone directly. Figures checked October 2026.
Key LBS to KG Terms Explained
These units and rules explain the exact factor behind every lbs to kg answer on this page and why UK and US labels differ.
- Avoirdupois pound
- The everyday pound used for body weight, food and freight, abbreviated lb. It is defined as exactly 0.45359237 kilograms and is divided into 16 ounces, which is why the converter can show pounds and ounces.
- Kilogram
- The base unit of mass in the International System of Units, equal to 1,000 grams. One kilogram is about 2.20462 pounds, which is the factor used when the tool converts kg to lbs.
- Stone
- A British unit of body weight equal to 14 pounds, or about 6.35 kilograms. A weight of 150 lb is 10 stone 10 pounds, which the converter shows beside the metric result for UK readers.
- International yard and pound
- The 1959 agreement that fixed the pound at exactly 0.45359237 kilograms in the UK, the US and other Commonwealth countries, ending small national differences in the value of the pound.
- Metric labelling rule
- The UK legal requirement that goods sold in England, Scotland and Wales are weighed in grams or kilograms. An imperial figure may appear alongside, but it must not stand out more than the metric one.
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How we checked this tool: the Tools Veria Editorial Team built this tool by hand, checked it against the official rules or published standards where they apply, and tested it against worked examples. Results are estimates for planning, not personal financial or tax advice. Read our editorial policy and disclaimer, or report an error.
Frequently Asked Questions
How many kg is 1 lb exactly?
One pound is exactly 0.45359237 kilograms, or about 453.6 grams. The value was set by international agreement in 1959, so it is the same in the US, the UK and every other country that uses the pound.
Is it lb or lbs?
Both are correct. The official abbreviation for pound is lb, from the Latin libra, and lbs is a common informal plural used on scales and labels. Scientific and technical writing usually keeps lb for both singular and plural.
How many kg is 200 lbs?
200 lbs is 90.72 kg. Multiply 200 by 0.45359237 to get 90.718 kilograms. In stone that is 14 st 4 lb, because 200 divided by 14 is 14 stone with 4 pounds left over.
Is dividing by 2.2 accurate enough?
Dividing by 2.2 gives an answer about 0.2% too high, so 100 lb becomes 45.45 kg instead of 45.36 kg. That is fine for body weight or luggage, but use the exact factor for medicine, shipping or science.
Is a pound a unit of mass or weight?
Strictly, the pound used here is a unit of mass, the avoirdupois pound, just like the kilogram. In everyday speech both are called weight, and on Earth a 1 lb mass always balances a 0.4536 kg mass.
How do I convert stone and pounds to kg?
Multiply the stone by 14, add the extra pounds, then multiply by 0.45359237. For example, 11 st 6 lb is 154 + 6 = 160 lb, which is 72.57 kg.