Lbs to Kg Converter
Convert a weight from pounds to kilograms using the exact international avoirdupois factor. Choose between a simple pounds input or a pounds-and-ounces input for body weight and food labels. Switch to reverse mode to convert kilograms back to pounds. Results appear in kilograms, grams, ounces, metric tons, and the UK stones-and-pounds form.
Formula
Worked example
150 lb = 150 × 0.45359237 = 68.0389 kg = 68,038.9 g = 68 kg 38.9 g. In stones: 150 ÷ 14 = 10 st 10 lb. Reverse: 70 kg ÷ 0.45359237 = 154.3236 lb = 154 lb 5.2 oz.
How to convert pounds to kilograms
Multiply the number of pounds by 0.45359237 to get kilograms. This factor is the exact definition of the international avoirdupois pound set by NIST and equivalent bodies. Because the factor is exact, the conversion is perfectly precise: 10 lb = 4.5359237 kg and 200 lb = 90.718474 kg. For a fast mental estimate, halve the pound value and subtract about 10 percent (150 lb: halve to 75, subtract 7.5 = 67.5 kg, close to the exact 68.04 kg). For quick division, you can also divide pounds by 2.205 to get an approximation accurate to three significant figures.
Pounds and ounces mode
Body weight on bathroom scales and birth weights on medical charts are often given in a combined format such as "10 lb 4 oz". Switch the input style to "Pounds + ounces" and enter each part separately. The calculator converts the ounce portion to a decimal fraction of a pound (ounces divided by 16), adds it to the pound value, then multiplies by 0.45359237. A newborn weighing 7 lb 5 oz is (7 + 5/16) = 7.3125 lb = 3.317 kg.
Reverse conversion: kilograms to pounds
Switch the direction to "Kilograms to pounds" to reverse the calculation. The converter divides the kilogram value by 0.45359237 (equivalent to multiplying by 2.20462262). It also splits the result into whole pounds and remaining ounces for easy reading on US and UK scales. Example: 68 kg / 0.45359237 = 149.91 lb = 149 lb 14.6 oz.
Pounds, kilograms, grams, stones, and metric tons
The kilogram is the SI base unit of mass and the standard almost everywhere outside the United States. The gram equals one thousandth of a kilogram and is common in food nutrition labels and science. The metric ton (tonne) is 1,000 kg, useful for industrial or freight weights. In the United Kingdom and Ireland, body weight is traditionally given in stones and pounds, where one stone equals 14 pounds. This converter shows every common unit so you can read whichever format you need without a second calculation.
Common pounds to kilograms conversions
| Pounds (lb) | Kilograms (kg) | Grams (g) | Stones + lb |
|---|---|---|---|
| 1 | 0.4536 | 453.6 | 0 st 1.0 lb |
| 5 | 2.2680 | 2268.0 | 0 st 5.0 lb |
| 10 | 4.5359 | 4535.9 | 0 st 10.0 lb |
| 25 | 11.3398 | 11339.8 | 1 st 11.0 lb |
| 50 | 22.6796 | 22679.6 | 3 st 8.0 lb |
| 100 | 45.3592 | 45359.2 | 7 st 2.0 lb |
| 125 | 56.6990 | 56699.0 | 8 st 13.0 lb |
| 150 | 68.0389 | 68038.9 | 10 st 10.0 lb |
| 175 | 79.3787 | 79378.7 | 12 st 7.0 lb |
| 200 | 90.7185 | 90718.5 | 14 st 4.0 lb |
| 250 | 113.3981 | 113398.1 | 17 st 12.0 lb |
| 500 | 226.7962 | 226796.2 | 35 st 10.0 lb |
| 1000 | 453.5924 | 453592.4 | 71 st 6.0 lb |
Based on the exact factor 1 lb = 0.45359237 kg.
Frequently asked questions
How many kilograms are in a pound?
Exactly 0.45359237 kilograms. This is the internationally agreed definition of the avoirdupois pound. For a quick estimate use 0.454, or divide pounds by 2.205, but the full 8-digit factor gives the most accurate result.
How do I convert pounds and ounces to kilograms?
First convert the ounce portion to pounds by dividing by 16, then add it to the whole pounds. Multiply the total by 0.45359237. Example: 10 lb 8 oz = 10 + 8/16 = 10.5 lb = 10.5 × 0.45359237 = 4.7627 kg. You can also switch to the pounds-and-ounces input mode in this calculator and it does the step automatically.
How do I convert kilograms back to pounds?
Divide the kilogram value by 0.45359237, or multiply by 2.20462262. Example: 70 kg ÷ 0.45359237 = 154.32 lb. For the ounce remainder: (154.32 - 154) × 16 = 5.1 oz, so 70 kg = 154 lb 5.1 oz. Use the reverse mode in this calculator to get this automatically.
What is 150 pounds in kilograms?
150 pounds equals 68.0389 kilograms (150 × 0.45359237). In stones and pounds that is 10 stone 10 pounds. In grams it is 68,038.9 g.
What is the quick mental method for pounds to kilograms?
Halve the pounds value and subtract about 10 percent of that half. For 150 lb: half is 75, 10% of 75 is 7.5, so 75 - 7.5 = 67.5 kg (exact is 68.04 kg, error under 1%). Alternatively, divide by 2.205 for a result accurate to three significant figures.
How many grams are in a pound?
One pound equals 453.59237 grams (0.45359237 kg × 1,000). Ten pounds equals 4,535.9 g, and 100 pounds equals 45,359.2 g.