How this works
1 kg ≈ 2.20462 lb (the reciprocal of the exact 1 lb = 0.45359237 kg defined in the 1959 international yard-and-pound agreement). Useful for body weight when crossing imperial/metric boundaries, gym plate calculations, shipping weights, and any cooking recipe written in pounds.
The formula
For mental conversion, multiply kg by 2.2 — gives ~0.2% error. So 70 kg ≈ 154 lb (actual 154.32), 80 kg ≈ 176 lb (actual 176.37). The ÷ 0.45359237 form looks intimidating but is exact; the × 2.20462 form is one rounding step removed but easier to remember.
Example calculation
- 1 kg = 2.205 lb
- 5 kg = 11.02 lb
- 70 kg = 154.32 lb (≈ adult weight)
- 23 kg = 50.71 lb (typical airline checked-bag limit)
Frequently asked questions
Why is the conversion 2.20462 and not a round number?
Because the kilogram and the pound were defined independently — the kg from a fraction of the Earth's circumference (later from a platinum-iridium prototype, now from physical constants), the pound from medieval English commerce. They were only formally pinned together in 1959 with 1 lb = 0.45359237 kg. The 2.20462 is just 1 / 0.45359237.
How heavy is the typical airline carry-on / checked bag in lb?
Typical carry-on limits are 7-10 kg = 15.4-22 lb. Checked-bag limits run 20-23 kg = 44.1-50.7 lb in economy, 30-32 kg = 66.1-70.5 lb in business/first. The US 50-lb domestic checked-bag limit comes out to 22.68 kg, which is why 23 kg is so common as the international rounded equivalent.