kg = lbs × 0.453592
Multiply pounds by 0.453592 to get kilograms.
| Pounds | Kilograms |
|---|---|
| 1 lbs | 0.454 kg |
| 10 lbs | 4.536 kg |
| 50 lbs | 22.680 kg |
| 100 lbs | 45.359 kg |
| 120 lbs | 54.431 kg |
| 130 lbs | 58.967 kg |
| 140 lbs | 63.503 kg |
| 150 lbs | 68.039 kg |
| 160 lbs | 72.575 kg |
| 175 lbs | 79.379 kg |
| 200 lbs | 90.718 kg |
The formula kg = lbs × 0.453592 comes directly from the 1959 international definition of the avoirdupois pound as exactly 0.45359237 kilograms. This makes the conversion exact, not approximate. The commonly used 0.453592 rounds to 6 significant figures, introducing an error of less than 0.0001 grams per pound — negligible for any practical application.
A quick mental shortcut: divide pounds by 2.2. This gives results within 0.2% of the precise answer for most body weight values (150 lbs ÷ 2.2 = 68.18 kg, vs. exact 68.04 kg). For a closer estimate, divide by 2.205 instead, which is accurate to within 0.02%.
Clinical medication dosing: Drug doses in hospitals are calculated per kilogram of body weight. A 160 lb patient weighs 72.6 kg. Dosing at 15 mg/kg would require 72.6 × 15 = 1,089 mg. US healthcare providers must convert patient weights reported in pounds to kilograms for all clinical dosing calculations.
International shipping: US domestic shipping uses pounds; international carriers and customs use kilograms. A 30 lb package = 13.6 kg. A 50 lb package = 22.7 kg. USPS customs forms require weight in kilograms for international shipments, even though domestic handling uses pounds.
Combat sports weight classes: UFC, boxing, and wrestling weight classes are defined in pounds in the US but kilograms internationally. UFC lightweight is 155 lbs = 70.3 kg. UFC heavyweight is up to 265 lbs = 120.2 kg. International broadcasts and records use kilograms.
Newborn and pediatric weights: Hospitals in the US record birth weights in pounds and ounces; international records use kilograms. An 8 lb 6 oz baby = 8.375 lbs = 3.80 kg. A 7 lb baby = 3.18 kg. Parents comparing their baby's weight to international growth charts need this conversion.
| Pounds | Kilograms |
|---|---|
| 100 lbs | 45.4 kg |
| 120 lbs | 54.4 kg |
| 130 lbs | 59 kg |
| 140 lbs | 63.5 kg |
| 150 lbs | 68 kg |
| 160 lbs | 72.6 kg |
| 175 lbs | 79.4 kg |
| 185 lbs | 83.9 kg |
| 200 lbs | 90.7 kg |
| 220 lbs | 99.8 kg |
Converting pounds to kilograms is essential for Americans working with international systems — including healthcare, science, shipping, and nutrition. Clinical settings worldwide use kilograms for all weight-based medication dosing; a US patient's pound-based weight must be converted before calculating drug doses, anesthesia, or chemotherapy. International nutrition guidelines and research studies always report weight in kilograms — anyone following a metric-based diet plan (protein per kg of body weight) needs this conversion. Online fitness communities, wearables, and apps may display weight in either unit depending on the user's region settings. Travelers carrying checked luggage from the US to metric countries need to know their bag's kilogram weight before reaching the airport. Scientists and engineers working in the US but publishing internationally must always convert to SI units.
1 pound equals exactly 0.45359237 kilograms. For everyday use, 1 lb ≈ 0.4536 kg.
Multiply the number of pounds by 0.453592. For example, 150 lbs × 0.453592 = 68.04 kg.
200 lbs = 200 × 0.453592 = 90.72 kg.
150 lbs = 150 × 0.453592 = 68.04 kg.
A kilogram is heavier than a pound. 1 kg = 2.20462 lbs. So 1 kilogram weighs more than twice as much as 1 pound.
For more weight conversions, see the full Weight Converter.