Converters
Convert common pounds, kilograms, ounces, and grams.
Enter your numbers to see the answer.
Weight converter guide
The weight converter turns ounces, pounds, grams, and kilograms into one another through the kilogram, the SI base unit of mass. Strictly these are all units of mass, and what a kitchen or bathroom scale reports is mass calibrated against standard gravity, so “weight” here means the everyday sense. The link between the two systems is exact: since 1959 the avoirdupois pound has been defined as 0.45359237 kg, and the ounce is one sixteenth of that, 28.349523125 g. Everything else is powers of ten. Use it for recipes written in grams, package weights, luggage limits, and body-weight comparisons. It does not cover troy ounces (precious metals, 31.1035 g), fluid ounces (a volume, not a mass), stones, or tons; the units section shows how to handle those. Body-weight and shipping tools on the site use the same factors, so their answers agree with this page.
Mass (to) = mass (from) × kilograms per from-unit ÷ kilograms per to-unit. Factors (kg): ounce 0.028349523125, pound 0.45359237, gram 0.001, kilogram 1.
Worked example with the defaults: 1 pound to kilograms. The pound factor is exact, so 1 × 0.45359237 = 0.45359237 kg, which the converter rounds to 0.45 kg. The detail rows show the same mass as 453.59 g and 1 lb. Reverse it to check: 1 kg ÷ 0.45359237 = 2.2046 lb. A more typical body-weight entry, 150 pounds, gives 150 × 0.45359237 = 68.04 kg, and a recipe amount of 500 g gives 0.5 ÷ 0.45359237 = 1.1 lb, or 500 ÷ 28.349523125 = 17.64 oz.
Enter ounces, pounds, grams, or kilograms as a decimal; write 2 lb 4 oz as 2.25 lb or 36 oz. Results show two decimals, so 1 lb reads 0.45 kg while the gram row keeps the finer 453.59 g. For a stone, multiply by 14 lb (6.35 kg). A metric ton is 1,000 kg, a U.S. short ton is 2,000 lb (907.18 kg), and a UK long ton is 2,240 lb (1,016.05 kg). Troy ounces used for gold are 31.1035 g, not 28.35 g.
Unit conversion is exact when the conversion factor is exact, so the only real uncertainty here is rounding and the precision of your input. Where a unit has more than one definition — US versus imperial measures, or short versus metric tons — the wrong variant produces a plausible-looking but wrong answer. The units note above states which definition this page uses. On this page the figure rests entirely on value, from and to, so start there if the weight converter returns something you did not expect.
Good to know: fluid ounces measure volume and cannot be converted here; 8 fl oz of water is about 8.3 oz by mass, and 8 fl oz of flour is about 4 oz. Do not round the pound to 0.45 kg when the result feeds another calculation; 200 lb is 90.72 kg with the exact factor but 90 kg with the rounded one. The word “ton” alone is ambiguous between 907 kg and 1,000 kg, a 10% gap that matters in freight quotes.
Conversion results use stated mathematical factors and display precision. For regulated, medical, engineering, or contractual work, confirm the required standard and precision.
Sources
How it works
Convert common pounds, kilograms, ounces, and grams. This tool explains the calculation so you can adjust the assumptions to match your situation.
Worked example
With Value = 1 · From = pounds · To = kilograms → 0.45 kilograms (1 pounds converted to kilograms). Change an input above and this example updates with your numbers.
Common questions
1 pound is exactly 0.45359237 kg, or 453.59 g, and the converter shows 0.45 kg at two decimals. Divide pounds by 2.2046 or multiply by 0.4536 for a quick answer; 150 lb is 68.04 kg and 180 lb is 81.65 kg.
1 kilogram is 2.2046 pounds (1 ÷ 0.45359237), or 35.274 ounces. A useful rule is to double the kilograms and add 10%: 70 kg → 140 + 14 = 154 lb, against the exact 154.32 lb.
One avoirdupois ounce is 28.349523125 g exactly, one sixteenth of the pound. 100 g is 3.53 oz, and 500 g is 17.64 oz. A troy ounce, used for gold and silver, is a different unit of 31.1035 g.
A metric ton (tonne) is 1,000 kg, or 2,204.62 lb. A U.S. short ton is 2,000 lb, or 907.18 kg, and a UK long ton is 2,240 lb, or 1,016.05 kg. Enter 1,000 kg or 2,000 lb here to convert either.
Not in physics: mass is the amount of matter, weight is the gravitational force on it, measured in newtons. Scales are calibrated so the number they show is mass under standard gravity, so for shopping, cooking, and body weight the two words describe the same figure.