⚖️ Pound to Kilogram Converter
Free online tool to convert Pound (lb) to Kilogram (kg). Enter a value and get instant, accurate results.
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Pound to Kilogram Conversion Table
| Pound (lb) | Kilogram (kg) |
|---|---|
| 1 lb | 0.45359237 kg |
| 5 lb | 2.2679619 kg |
| 10 lb | 4.5359237 kg |
| 50 lb | 22.679619 kg |
| 100 lb | 45.359237 kg |
| 500 lb | 226.79619 kg |
About Pound to Kilogram Conversions
Converting Pound (lb) to Kilogram (kg) is one of the most common weight conversions. Enter a value below for an instant answer.
The conversion factor is: 1 lb = 0.45359237 kg. To convert manually, multiply your value by 0.45359237. As a quick example: 10 lb = 4.5359237 kg.
For reference: this page provides a lb-to-kg conversion table covering common values, the exact mathematical formula, and frequently asked questions.
Frequently Asked Questions
What is 180 pounds in kilograms?
180 lb × 0.453592 = 81.65 kg. For a quick check: half of 180 is 90, minus 10% of that (9) gives 81 — within a kilogram of the exact answer.
How do I convert pounds to kilograms in my head?
Halve the pounds, then subtract 10% of the result. For 160 lb: half is 80, minus 8 = 72 kg (exact: 72.6 kg). This works because 0.45 = 0.5 × 0.9.
Why is the pound legally defined in kilograms?
Since the 1959 international yard and pound agreement, one avoirdupois pound is defined as exactly 0.45359237 kg. There is no independent physical pound standard — the kilogram (defined via Planck's constant since 2019) anchors both systems.
How much does a newborn baby weigh in pounds and kilograms?
Average full-term birth weight is about 7.5 lb (3.4 kg), with the typical range spanning 5.5–10 lb (2.5–4.5 kg). US hospitals record pounds and ounces; most other countries use kilograms and grams.
Are US pounds and UK pounds the same weight?
Yes — both use the avoirdupois pound of exactly 453.59237 grams. The difference between the countries is usage, not definition: the UK officially uses kilograms but colloquially expresses body weight in stones and pounds (1 stone = 14 lb).
Related Weight Conversions
Reference Charts
Pounds to Kilograms Conversion Chart
Quick-reference chart converting pounds (lbs) to kilograms (kg). Covers 1–500 lb at common intervals with the exact conversion formula.
Kilograms to Pounds Conversion Chart
Quick-reference chart converting kilograms (kg) to pounds (lbs). Covers 1–250 kg at common intervals with the exact conversion formula.
Ounces to Grams Conversion Chart
Quick-reference chart converting ounces (oz) to grams (g). Covers ½ oz to 64 oz — ideal for cooking, food packaging, and converting US recipes to metric.
Stone to Pounds Conversion Chart
Reference chart converting stone (st) to pounds (lb) and kilograms (kg). Covers 6 stone to 25 stone — the full UK adult body weight range.
Related Guides
Kilograms vs Pounds Explained
Kilograms and pounds both measure mass but belong to different systems. Learn the key differences, which countries use each unit, and the exact conversion factor.
6 min read
How to Convert Kilograms to Pounds
To convert kilograms to pounds, multiply by 2.20462. Learn the formula, a mental shortcut, a full reference table, and worked examples for common weights.
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All conversion results are provided for general informational purposes only. Our formulas use internationally recognized conversion factors; however, rounding may affect precision. Do not rely on these results for professional, medical, legal, or engineering decisions without independent verification. Read our full disclaimer.