150 lb to kg
- Pounds (lb)
- 150 lb
- Kilograms
- 68.0388555 kg
Checked against: Exact-fraction computation from the legal unit definitions
Pounds to kilograms converter
Convert pounds to kilograms (lbs to kg) with the exact factor, a conversion chart and worked steps.
By AdminDrafted with AI writing toolsUpdated Checked examples: 3
Kilograms
kg
Kilograms: 68.0388555 kg
- Conversion
- 150 lb = 68.0388555 kg
- 1 kg in pounds
- 2.204622622lb
150 lb is about 68.0388555 kg. In the other direction, 1 kg ≈ 2.20462262 lb.
Pounds to kilograms
Lbs to kg chart
| Pounds | Kilograms |
|---|---|
| 1 | 0.4536 |
| 5 | 2.268 |
| 10 | 4.5359 |
| 20 | 9.0718 |
| 50 | 22.6796 |
| 100 | 45.3592 |
| 120 | 54.4311 |
| 150 | 68.0389 |
| 180 | 81.6466 |
| 200 | 90.7185 |
| 220 | 99.7903 |
How it's calculated S
Conversion factor
Exact by definition.
Multiply
About the pounds to kilograms converter
To convert pounds to kilograms, multiply by 0.45359237; to convert back, multiply by 2.2046226218. For example, 150 lb is about 68.038856 kg. Displayed factors and results may be rounded.
Pounds are often used on parcel labels and equipment specifications. This is avoirdupois mass, rather than a force rating. If the source gives pounds plus ounces, combine them correctly before conversion. A carrier's billed weight can also depend on package dimensions.
The 1959 international yard and pound agreement defines the avoirdupois pound exactly: 1 lb = 0.45359237 kg.
Both units are defined exactly. Calculations use 50 significant digits and round only for display.
How to convert pounds to kilograms
Multiply pounds by 0.45359237 to get kilograms. 1 lb = 0.45359237 kg, so 150 lb = 68.04 kg and 200 lb = 90.72 kg. The factor is exact for the everyday pound used for body weight, food and parcels; for a quick estimate, divide by 2.2.
Where 0.45359237 comes from
The international yard and pound agreement of 1959 fixed the pound at exactly 0.45359237 kg (NIST). The factor is a definition, not a measurement, so it carries no rounding error.
So one pound is exactly 453.59237 g, and one ounce, a sixteenth of a pound, is exactly 28.349523125 g.
Pounds to kilograms chart
The kilogram values are exact; round them to the precision of your reading.
| Pounds (lb) | Kilograms (kg) |
|---|---|
| 1 | 0.45359237 |
| 2 | 0.90718474 |
| 5 | 2.26796185 |
| 10 | 4.5359237 |
| 25 | 11.33980925 |
| 50 | 22.6796185 |
| 100 | 45.359237 |
| 150 | 68.0388555 |
| 200 | 90.718474 |
| 250 | 113.3980925 |
A reading of 150.0 lb that is good to ±0.1 lb is good to ±0.045359237 kg, about ±45 g. Report it as 68.04 kg; the full 68.0388555 kg claims more precision than the scale has.
Pounds and ounces to kg
Turn the ounces into a fraction of a pound first: kg = (lb + oz ÷ 16) × 0.45359237. You can type 7 lb 8 oz as 7+8/16.
- A baby born at 7 lb 8 oz weighs 7.5 lb, which is 3.401942775 kg (3.40 kg).
- 3 lb 8 oz is 3.5 lb, or 1.587573295 kg.
- 8 oz is half a pound: 0.226796185 kg, or about 227 g.
Do not read 3 lb 8 oz as 3.8 lb. That gives 1.723651006 kg, about 136 g too much, because 0.8 lb is 12.8 oz.
Stones and pounds to kg
UK body weights are often written in stones and pounds, with 14 lb to the stone. 11 st 7 lb is 11 × 14 + 7 = 161 lb, which is 73.02837157 kg.
That is not 11.7 stone, which would be 163.8 lb, or 74.30 kg. The weight converter accepts 11 st 7 lb written out like that.
How to convert lbs to kg in your head
- Divide by 2.2. 200 lb gives 90.91 kg, 0.19 kg (0.21%) above the exact 90.718474 kg.
- Halve it, then take off a tenth. 200 lb → 100 → 90 kg. This multiplies by 0.45, so it runs 0.8% low: 0.718474 kg under for 200 lb.
Common mistakes
- Using 0.45 on large loads. The 0.8% shortfall hardly matters for body weight but is 7.18 kg on 2,000 lb of freight.
- Treating fluid ounces as ounces. A fl oz on a bottle measures volume. Turning it into kilograms needs the liquid's density.
- Converting a pound-force rating. Thrust, a bow's draw weight and a rope's breaking strength in pounds are forces. Multiplying by 0.45359237 gives kilograms-force; for newtons, use the force converter.
Related conversions
For the reverse direction, use kg to lbs. Lbs to stones covers UK body weights, and ounces to grams covers recipe amounts.
Worked examples
20 lb to kg
- Pounds (lb)
- 20 lb
- Kilograms
- 9.0718474 kg
Checked against: Exact-fraction computation from the legal unit definitions
200 lb to kg
- Pounds (lb)
- 200 lb
- Kilograms
- 90.718474 kg
Checked against: Exact-fraction computation from the legal unit definitions
Questions
How many kilograms are in one pound?
1 lb is about 0.45359237 kg. The 1959 international yard and pound agreement defines the avoirdupois pound exactly: 1 lb = 0.45359237 kg.
How do I convert pounds to kilograms?
Multiply by 0.45359237: 150 lb × 0.45359237 ≈ 68.038856 kg. To convert back, divide by the same factor. The factor shown may be rounded.
How can I estimate pounds in kilograms without a calculator?
Multiply by 0.45. This is 0.8% below the exact factor (about 0.45359237), so 150 lb comes out as 67.5 kg instead of 68.0389 kg.
About this calculator
Sources
Checked against references
This calculator includes 3 worked examples with independently sourced answers. They run in the test suite, and you can run them here too.