Convert LBS to KG

Pounds to kilograms – plus ounces and stone

Enter a weight in pounds and see the exact value in kilograms, grams, ounces, stone, tonnes and Indian units such as tola. The extra lines split your value into pounds and ounces and into stone and pounds, so you can check a baby's birth weight, a UK bathroom-scale reading or a recipe quantity at a glance. Use the swap button for kilograms to pounds.

One pound is defined as exactly 0.45359237 kilograms.

The formula

kg = lb × 0.45359237

kg = lb ÷ 2.20462

lb = kg × 2.20462

With ounces: kg = (lb + oz ÷ 16) × 0.45359. With stone: kg = (stone × 14 + lb) × 0.45359.

Worked examples

• 150 lb × 0.45359 = 68.04 kg.
• 200 lb = 90.72 kg.
• A 7 lb 8 oz baby = 7.5 lb = 3.40 kg.
• A 50 lb checked-bag limit = 22.68 kg (airlines in kg-using countries use 23 kg).
• A 45 lb barbell plate = 20.41 kg; a 45 lb Olympic bar = 20.41 kg.
• A 1 lb pack of butter = 453.6 g.
• 11 st 4 lb = 158 lb = 71.67 kg.

Quick mental estimate

Halve the pounds and take away 10%: 180 lb → 90 → minus 9 = 81 kg (exact: 81.65 kg). That gets you within about 1%. For a rougher figure, just halve: 100 lb ≈ 50 kg (exact 45.4 kg) – but note that halving overestimates by 10%.

Pounds to kilograms chart

Stone and pounds to kilograms

In the UK and Ireland body weight is often given in stone and pounds. One stone is 14 lb, or 6.35 kg.

Gym weights in pounds and kilograms

Gyms in the US use pound plates (2.5, 5, 10, 25, 35, 45 lb), while most of the world uses kilogram plates (1.25, 2.5, 5, 10, 15, 20, 25 kg). A 45 lb plate is 20.4 kg – very close to a 20 kg plate, but not identical, so totals drift on heavy lifts: 405 lb (a bar plus four 45 lb plates per side) is 183.7 kg, not 180. Competition powerlifting records are kept in kilograms.

Pounds in shipping and luggage

Couriers bill by weight bands, typically rounded up to the next pound or half kilogram. A 2.2 lb parcel is 1 kg. When converting a limit, round down to stay safe: a 23 kg airline limit is 50.7 lb, so aim for 50 lb on a US scale. Volumetric (dimensional) weight is calculated separately from the box size.

Where the pound comes from

The word pound comes from the Latin libra pondo, 'a pound by weight' – which is why it is abbreviated lb. Many slightly different pounds existed across Europe. The avoirdupois pound of 16 ounces became the English standard, and in 1959 the international pound was fixed at exactly 0.45359237 kg. The troy pound (12 troy ounces, 373.24 g) is still used for precious metals.

Accuracy and rounding

Body weight: one decimal place in kilograms. Cooking: the nearest 5–10 g. Medicine dosages based on body weight: use the full precision and confirm with a professional. The converter shows up to eight significant figures, and the download lists your value in every unit.

Baby birth weights: pounds and ounces to kg

Body weight and BMI

Many health calculators, including the BMI calculator, work in kilograms and metres. BMI is weight in kilograms divided by height in metres squared, so you need both conversions: a person who weighs 165 lb (74.8 kg) and is 5 ft 9 in tall (1.753 m) has a BMI of 74.8 ÷ 1.753² = 24.4. In the US the same figure is calculated as 703 × lb ÷ in², which gives the same result. BMI is a rough screening tool and does not account for muscle mass, age or body shape.

Pounds in recipes and groceries

US recipes and supermarkets sell meat, cheese, flour and produce by the pound, while most other countries use kilograms. Half a pound (8 oz) is 227 g, a quarter pound is 113 g – the origin of the 'quarter pounder' burger, which weighs 113 g of raw beef. A 5 lb bag of flour is 2.27 kg; a 10 lb bag of rice is 4.54 kg. Prices per pound can be compared with prices per kilogram by multiplying the per-pound price by 2.2046: $3.99/lb equals $8.80/kg.

Weight versus mass

Strictly, kilograms and pounds measure mass – the amount of matter – while weight is the force of gravity on that mass. Bathroom scales measure force and display it as mass assuming Earth's gravity. That is why you would 'weigh' less on the Moon even though your mass in kilograms is unchanged. The pound-force (lbf) and the kilogram-force (kgf) are force units used in engineering; 1 lbf = 4.448 newtons. For everyday conversions the distinction does not matter, and the converter treats lb and kg as mass units.

Common mistakes

• Dividing by 2 instead of 2.2046 – that overestimates the kilograms by 10%.
• Treating 7.8 lb as 7 lb 8 oz – it is 7 lb 12.8 oz. Use the lb + oz line.
• Mixing up troy pounds (precious metals, 373 g) and avoirdupois pounds (454 g).
• Rounding 0.4536 to 0.45 for heavy loads – the error is about 0.8%, or 8 kg per tonne.

Tonnes, short tons and long tons

Heavy loads add another trap: the US short ton is 2,000 lb (907.2 kg), the UK long ton is 2,240 lb (1,016 kg), and the metric tonne is 1,000 kg (2,204.6 lb). Vehicle weights, freight quotes and shipping manifests may use any of the three, so always check which ton is meant before converting.

Kilograms to pounds, the reverse check

To check a conversion in the other direction, multiply kilograms by 2.20462. 70 kg × 2.20462 = 154.3 lb; 90 kg = 198.4 lb; 100 kg = 220.5 lb. A useful sanity check is that the number of pounds should always be a little more than double the number of kilograms. If your result is less than double, you have probably multiplied when you should have divided. The kg to lbs converter gives the reverse result with the same pound + ounce and stone breakdown.

Pounds around the world

The United States uses pounds for almost everything, from body weight to groceries. The United Kingdom officially uses kilograms for trade but people still describe body weight in stone and pounds, and beer is sold in pints. Canada sells food in grams and kilograms but many people state their weight in pounds. India, Australia and most other countries use kilograms throughout, although older generations in some places still use local units such as the tola for gold or the seer and maund for produce. Whatever the local habit, the conversion factor is the same everywhere.

Pounds to kg in a spreadsheet

In Excel or Google Sheets use =A2*0.45359237 or =CONVERT(A2,"lbm","kg"). For pounds in A2 and ounces in B2, use =(A2+B2/16)*0.45359237. For stone in A2 and pounds in B2, use =(A2*14+B2)*0.45359237. Round with =ROUND(…,1) for body weight, or keep three decimals for shipping manifests and laboratory records where grams matter.

Privacy

The converter runs entirely in your browser. Nothing you type is sent to a server, your values are not tracked, and once the page has loaded it keeps working offline – useful in a workshop, a kitchen, a gym or on a plane.

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