Convert pounds to kilograms instantly (and back) with the exact 0.45359237 definition — for metric medical forms, international shipping, and metric gyms.
1 lb = 0.45359237 kg
1 lb = 0.45359237 kg · multiply by 0.45359237
Conversions run instantly on your device — nothing is sent anywhere.
Convert pounds to kilograms — and back — using the exact definition (1 lb = 0.45359237 kg).
Loads with lb → kg preselected: this page is for the pound-first reader filling in a metric
form, shipping abroad, or training in a metric gym. (Metric-first? The
kg to lbs converter starts the other way and covers luggage limits.)
The formula
kg = pounds × 0.45359237 · pounds = kg × 2.2046226. Mental math: halve it, subtract a
tenth of the half — 200 lb → 100 − 10 = 90 kg (true 90.72).
Common values
pounds
kg
pounds
kg
1
0.454
150
68.04
5
2.27
175
79.38
10
4.54
200
90.72
25
11.34
225
102.06
50
22.68
250
113.40
100
45.36
300
136.08
Forms, freight, and the gym
Medical and official forms outside the US ask for kilograms — and the “just halve it”
shortcut writes you 10% heavier than you are; the table above has the honest numbers.
Shipping abroad is billed in kg (see the dimensional-weight note in the FAQ). Lifting:
US plates don’t translate to round metric numbers — the FAQ maps the classic bar-and-plate
milestones. UK readers weighing themselves in stones-and-pounds have a
dedicated stone to kg page, because 12 st 6 lb is its own
arithmetic.
Private by design
The conversion runs on your device as you type — nothing is sent or stored. All six categories
live in the unit converter.
Last updated:
Frequently asked questions
What is the exact pounds to kg formula?
Multiply pounds by 0.45359237 — the exact legal definition of the avoirdupois pound since 1959. So 150 lb = 68.04 kg, precisely. Reverse: kg × 2.2046226 = lb.
What is the quick mental trick for lbs to kg?
Halve the pounds, then take off about 10% of that: 180 lb → 90 − 9 = 81 kg (true: 81.65). Just halving overshoots by 10% — 180 lb is not 90 kg, a common error on metric medical intake forms.
How do US gym weights read in kilograms?
The US 45 lb bar is 20.4 kg (metric bars are a flat 20 kg — close but not identical). Plates: 45 lb = 20.4 kg, 35 lb = 15.9 kg, 25 lb = 11.3 kg, 10 lb = 4.5 kg. The famous 225 lb bench (bar + two 45s per side) is 102.1 kg; 315 lb is 142.9 kg.
How do shipping weights convert?
International carriers charge on kilograms: a 10 lb parcel is 4.54 kg, a 50 lb box is 22.68 kg. Watch dimensional weight too — it is computed in metric (cm³/5000) on most international services, so both the scale weight and the size convert.
Convert length, weight, temperature, volume, area, and speed between 46 units using exact international definitions — instantly, with the formula shown.
Convert kilograms to pounds (and back) using the exact 2.2046226 factor — body weight, luggage limits, and gym plates, converted instantly on your device.