lbs to kg Converter
Convert pounds to kilograms for fitness, shipping, and international weight comparison.
120 pounds equals 54.43 kg. One pound is exactly 0.45359237 kg, so multiply pounds by 0.4536 to convert to kilograms. Common values: 150 lb = 68.04 kg, 180 lb = 81.65 kg, 200 lb = 90.72 kg. Use the converter below for any weight.
How It Works
Formula: lbs to kg = value × 0.45359237
Example: 150 lbs = 68.038855 kg
Note: 1 pound equals 0.45359237 kilograms.
Common Uses
Quick Conversion Table
| lbs | kg |
|---|---|
| 1 | 0.4536 |
| 5 | 2.268 |
| 10 | 4.5359 |
| 25 | 11.3398 |
| 50 | 22.6796 |
| 100 | 45.3592 |
| 150 | 68.0389 |
| 200 | 90.7185 |
Rounding Rule
Rounded to 6 decimal places
Error Margin
±0.00001 kg
Precision Guidance
For everyday use, round to 2 decimal places.
Common Mistakes
Do not confuse with troy pounds used for precious metals.
Frequently Asked Questions
What is 1 lb in kg?
1 pound equals 0.45359237 kilograms using the US avoirdupois standard.
How do I convert lbs to kg?
Multiply the pound value by 0.45359237. For example, 150 lbs × 0.45359237 = 68.04 kg.
How many kg is 120 lbs?
120 pounds equals 54.431 kilograms (120 × 0.45359237 = 54.4311 kg).
How many kg is 150 lbs?
150 pounds equals 68.039 kilograms (150 × 0.45359237 = 68.0389 kg).
How many kg is 180 lbs?
180 pounds equals 81.647 kilograms (180 × 0.45359237 = 81.6466 kg).
How many kg is 200 lbs?
200 pounds equals 90.718 kilograms (200 × 0.45359237 = 90.7185 kg).
More Converters You May Like
kg to lbs Converter
Convert kilograms to pounds for American fitness, shipping, and international weight comparison.
oz to Grams Converter
Convert ounces to grams for American cooking, baking, and postal weight measurement.
Grams to oz Converter
Convert grams to ounces for following American recipes and reading US nutrition labels.
Exact Constants & Authoritative Sources
Every conversion on this page uses the fixed, internationally agreed constants below — drawn from NIST and the SI Brochure. No values are estimated or rounded as if exact. See the full list on our Sources & Standards page.
- EXACT1 pound (lb, avoirdupois) = 0.45359237 kilograms (exact)
- EXACT1 ounce (oz, avoirdupois) = 28.349523125 grams (exact, 1/16 lb)
- EXACT1 stone (st) = 6.35029318 kilograms (exact, 14 lb)
- EXACT1 short ton (US) = 907.18474 kilograms (exact, 2000 lb)
Common Pitfalls & How to Avoid Them
Mass vs. weight
The pound and kilogram are units of MASS, not force. On Earth, mass and "weight" read the same number in practice, but a 70 kg mass weighs less on the Moon. UnitFig converts mass; for scientific force you need newtons (1 lbf = 4.4482216152605 N, exact).
Avoirdupois vs. troy ounce
Cooking and body weight use the avoirdupois ounce (28.349523125 g). Gold and precious metals use the troy ounce (31.1034768 g). Never mix them — the error is about 10%.
Rounding the factor
Using 2.2 instead of the exact 2.20462262 overstates small errors at large values. For medical dosing or competition weight classes, keep the full factor or use a converter.
A unit-conversion reference site has no manufacturer-specific or device calibration parameters, so "layered tuning" does not apply here. The only real error-handling is input validation: the converter rejects non-numeric, empty, or out-of-range entries and shows a clear message, then falls back to exact constants above. No estimated or rounded figures are ever presented as exact.
Authoritative sources for this page
- NIST (U.S. National Institute of Standards and Technology) — NIST SP 330 — The International System of Units (SI), 2019 edition
Last Updated 2026 | This converter was reviewed for accuracy