Converting pounds to kilos (and back) shows up at the gym (dumbbells in lbs), at the airport (baggage limit in lbs), in US recipes and in Anglo medical data. Here you have the exact formula, ready table, mental trick and references for body weight, luggage and gym.
Exact formula
1 pound (avoirdupois) = 0.45359237 kg (exact definition since 1959)
1 kg = 2.2046226218… pounds
Conversions:
- lbs → kg:
kilos = pounds × 0.45359237 - kg → lbs:
pounds = kilos × 2.20462262
Reference table (pounds → kilos)
| Pounds | Kilos (exact) | Kilos (rounded) | Context |
|---|---|---|---|
| 1 | 0.4536 | 0.45 | — |
| 5 | 2.2680 | 2.27 | Light dumbbell |
| 10 | 4.5359 | 4.54 | 10 lb dumbbell |
| 15 | 6.8039 | 6.80 | — |
| 20 | 9.0718 | 9.07 | Low carry-on limit |
| 22 | 9.9790 | 10.0 | Typical carry-on |
| 25 | 11.3398 | 11.3 | 25 lb dumbbell |
| 30 | 13.6078 | 13.6 | — |
| 35 | 15.8757 | 15.9 | — |
| 40 | 18.1437 | 18.1 | — |
| 45 | 20.4117 | 20.4 | Olympic 45 lb plate |
| 50 | 22.6796 | 22.7 | — |
| 100 | 45.3592 | 45.4 | — |
| 150 | 68.0389 | 68.0 | Body weight reference |
| 180 | 81.6466 | 81.6 | — |
| 200 | 90.7185 | 90.7 | — |
| 220 | 99.7903 | 99.8 | — |
| 250 | 113.398 | 113.4 | — |
| 300 | 136.078 | 136.1 | — |
Inverse table (kilos → pounds) – gym/body references
| Kilos | Pounds (exact) | Pounds (rounded) | Context |
|---|---|---|---|
| 1.25 | 2.76 | 2.75 | Fractional plate |
| 2.5 | 5.51 | 5.5 | Fractional plate |
| 5 | 11.02 | 11 | 5 kg plate |
| 10 | 22.05 | 22 | 10 kg plate |
| 15 | 33.07 | 33 | 15 kg plate |
| 20 | 44.09 | 44.1 | 20 kg plate |
| 25 | 55.12 | 55.1 | 25 kg plate |
| 50 | 110.23 | 110 | Light person |
| 60 | 132.28 | 132 | — |
| 70 | 154.32 | 154 | Average man |
| 80 | 176.37 | 176 | — |
| 90 | 198.42 | 198 | — |
| 100 | 220.46 | 220 | — |
| 110 | 242.51 | 243 | — |
| 120 | 264.55 | 265 | — |
Mental trick: “Divide by 2.2”
kg ≈ lbs / 2.2 (or kg ≈ lbs × 0.45)
| Pounds | Trick | Exact | Error |
|---|---|---|---|
| 100 | 45.45 | 45.36 | +0.2 % |
| 150 | 68.18 | 68.04 | +0.2 % |
| 200 | 90.91 | 90.72 | +0.2 % |
| 220 | 100.0 | 99.79 | +0.2 % |
Error ~+0.2 % (negligible for everyday use).
Inverse mental: lbs ≈ kg × 2.2 (ex: 70 kg × 2.2 = 154 lbs, actual 154.32).
Quick references by context
Body weight (common ranges)
| Description | Kilos | Pounds |
|---|---|---|
| Newborn baby | 3–4 kg | 6.6–8.8 lbs |
| 10-year-old child | 30–35 kg | 66–77 lbs |
| Average adult woman | 60–70 kg | 132–154 lbs |
| Average adult man | 75–85 kg | 165–187 lbs |
| Strength athlete (90 kg) | 90 kg | 198 lbs |
| Class I obesity (BMI 30, 1.75 m) | 92 kg | 203 lbs |
Air luggage (typical limits)
| Type | Usual limit (lbs) | Limit (kg) |
|---|---|---|
| Carry-on | 22 lbs | 10 kg |
| Checked | 50 lbs | 23 kg |
| Heavy checked | 70 lbs | 32 kg |
| Overweight | > 50 lbs | > 23 kg |
Tip: weigh your suitcase at home with a bathroom scale (you + suitcase − you) before heading to the airport.
Gym (plates and dumbbells)
| Standard | Large plate | Medium plate | Small plate |
|---|---|---|---|
| Metric (EU) | 25 kg | 20 / 15 / 10 kg | 5 / 2.5 / 1.25 kg |
| Imperial (US) | 45 lbs (20.4 kg) | 35 / 25 / 10 lbs | 5 / 2.5 lbs |
Olympic bar: 20 kg (men) / 15 kg (women) = 44 lbs / 33 lbs.
Standard bar (1 in): ~10–12 kg.
Conclusion
- Exact: lbs × 0.45359237 = kg.
- Mental: lbs / 2.2 ≈ kg (error +0.2 %).
- Table: print the gym/luggage reference one.
- Tool: unit converter for any value.