Weight & Mass Converter
Free weight converter: kg to lbs, lbs to kg, grams to ounces, stone to kg and more, using the exact 0.45359237 kg pound. Instant results, no signup.
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All units
| Unit | Value | Copy |
|---|---|---|
| Milligrammg | 1000000 | |
| Gramg | 1000 | |
| Kilogramkg | 1 | |
| Metric Tont | 0.001 | |
| Ounceoz | 35.273962 | |
| Poundlb | 2.2046226 | |
| Stonest | 0.15747304 | |
| US TonUS ton | 0.0011023113 | |
| Imperial Tonlong ton | 0.00098420653 |
Popular conversions
How weight conversion works
Every unit on this page is stored as a number of kilograms, and a conversion is two steps: multiply by the source unit's size in kilograms, then divide by the target unit's size. The factors that matter most are exact by definition. The international avoirdupois pound is 0.45359237 kg exactly, the ounce is 1/16 of that (28.349523125 g), and the stone is 14 pounds (6.35029318 kg).
Because these definitions are exact, the only rounding you see comes from how many digits are displayed. The converter keeps 8 significant figures; the tables below show 6.
Strictly, kilograms, grams, pounds and ounces measure mass, the amount of matter. A bathroom scale or kitchen scale reports mass even though everyday speech calls it weight, so you can convert scale readings here directly. Weight as a force is measured in newtons and changes with gravity; mass does not.
Worked examples
Body weight, pounds to kilograms
150 lb × 0.45359237 = 68.04 kg. For a quick check, halve the pounds and take off 10%: 75 − 7.5 = 67.5 kg, within 1% of the exact figure.
Kitchen scale, grams to ounces
750 g ÷ 28.349523 = 26.46 oz, which is 1 lb 10.5 oz. Divide by 16 to get pounds and keep the remainder in ounces.
UK weight in stones and pounds
11 st 4 lb is 11 × 14 + 4 = 158 lb. 158 × 0.45359237 = 71.67 kg. Convert the stones to pounds first; typing 11.4 stone gives a different (wrong) answer, because 4 lb is 0.29 of a stone, not 0.4.
Freight, metric tonnes to US tons
A 20-tonne load is 20 × 1,000 ÷ 907.18474 = 22.05 US (short) tons, but only 19.68 UK (long) tons. Always check which ton a quote means.
Everyday weights in kilograms, pounds and ounces
| kg | lb | oz | st | |
|---|---|---|---|---|
| 100 g pack | 0.1 | 0.220462 | 3.5274 | 0.0157473 |
| Half a kilo | 0.5 | 1.10231 | 17.637 | 0.0787365 |
| 1 kg bag of sugar | 1 | 2.20462 | 35.274 | 0.157473 |
| Newborn baby (example) | 3.5 | 7.71618 | 123.459 | 0.551156 |
| Checked bag limit (many airlines) | 23 | 50.7063 | 811.301 | 3.62188 |
| Adult, 60 kg | 60 | 132.277 | 2,116.44 | 9.44838 |
| Adult, 70 kg | 70 | 154.324 | 2,469.18 | 11.0231 |
| Adult, 80 kg | 80 | 176.37 | 2,821.92 | 12.5978 |
| Adult, 100 kg | 100 | 220.462 | 3,527.4 | 15.7473 |
Common mistakes
- Using 2.2 for anything precise. 1 kg is 2.20462262 lb (NIST SP 811 defines the pound as 0.45359237 kg). The 0.2% error from 2.2 is fine for a scale reading but not for medication, shipping charges or a recipe scaled up 20 times.
- Mixing up fluid ounces and ounces. A fluid ounce measures volume; an ounce measures mass. 8 fl oz of water weighs about 8.3 oz, but 8 fl oz of flour weighs roughly half that. Use the volume converter for fl oz.
- Reading decimal pounds as pounds and ounces. 2.5 lb is 2 lb 8 oz, not 2 lb 5 oz. Multiply the decimal part by 16.
- Confusing the three tons. A metric tonne is 1,000 kg, a US short ton is 2,000 lb (907.18 kg) and a UK long ton is 2,240 lb (1,016.05 kg).
- Using troy ounces for groceries. Gold and silver are priced in troy ounces of 31.1035 g; food and parcels use the avoirdupois ounce of 28.3495 g.
Sources
Conversion charts
Frequently asked questions
How many pounds in a kilogram?
1 kilogram equals about 2.2046 pounds.
How many grams in an ounce?
1 ounce equals about 28.3495 grams.
How do I convert lbs to kg?
Multiply pounds by 0.45359237, the exact international definition. 150 lb × 0.45359237 ≈ 68.04 kg and 90 lb ≈ 40.82 kg. For a quick estimate, halve the pounds and take off 10%.
How many kg is a stone?
1 stone is exactly 14 pounds, which is 6.35029318 kg. A person weighing 11 st 6 lb weighs 160 lb, or about 72.6 kg.
What is the difference between weight and mass?
Mass is how much matter an object contains and is measured in kilograms. Weight is the force gravity puts on that mass. In everyday use, including on bathroom scales and food labels, the two words mean the same thing and are given in kg or lb.
Is weight the same as mass?
Not strictly. Mass (kg, lb, oz) is the amount of matter and does not change; weight is the force of gravity on that mass, measured in newtons. Scales show mass, so kg and lb readings convert directly.
How do I convert a weight to ounces?
Multiply pounds by 16, or divide grams by 28.3495. 3 lb is 48 oz, and 500 g is 17.64 oz.
How many grams are in a pound?
Exactly 453.59237 grams, usually rounded to 454 g.
How many pounds are in a stone?
14 pounds, which is 6.35 kg.