Pound to Kilogram
Free instant pound to kilogram converter. 1 lb = 0.453592 kg.
Common Pound to Kilogram values
| Pound (lb) | Kilogram (kg) |
|---|---|
| 1 | 0.453592 |
| 5 | 2.26796 |
| 10 | 4.53592 |
| 25 | 11.3398 |
| 50 | 22.6796 |
| 100 | 45.3592 |
| 500 | 226.796 |
| 1000 | 453.592 |
How does Pound to Kilogram conversion work?
Type a value in the Pound (lb) field and the equivalent in Kilogram (kg) appears instantly to the right. The math uses the exact formula shown above — no rounding errors, no approximations beyond standard floating-point precision. Use the swap button to flip the units and see the inverse conversion.
Pound. The standard imperial weight unit. Defined as exactly 0.45359237 kg since 1959.
Kilogram. The SI base unit of mass. About the weight of a litre of water.
⚡ Instant results
No submit button — the result updates as you type. Math runs entirely in your browser, so it’s as fast as your device.
📱 Use on any device
Works in any modern browser — Mac, Windows, Linux, iPhone, Android, tablets. No installation, no signup.
🎯 Accurate conversions
Conversion factors come from the official standard (NIST, BIPM, ISO definitions where applicable). Values are precise to standard floating-point limits.
🎁 Always free, no signup
Free, every time. No account, no email, no “trial” that becomes paid. Ad-supported so you never have to pay.
How it works — the formula
value_in_base = value × scale
For mass, scale = kilograms per unit (e.g. 1 lb = 0.45359237 kg exactly)The SI base unit for what laypeople call "weight" is the kilogram, redefined in 2019 in terms of the Planck constant h = 6.62607015 × 10⁻³⁴ J·s exactly (CGPM 26th meeting, Resolution 1). Strictly, weight is a force (mass × g) measured in newtons, but everyday usage and US-customary units treat it as mass. The international avoirdupois pound has been exactly 0.45359237 kg since the 1959 agreement.
Worked examples
- Inputs:
- 150 lb = ? kg
- Output:
- 150 × 0.45359237 = 68.0388555 kg
- Inputs:
- 8 oz = ? g
- Output:
- 8 × 28.349523125 = 226.796185 g (avoirdupois)
- Inputs:
- 1 t (metric) = ? short ton
- Output:
- 1 / 0.90718474 ≈ 1.1023 short tons
Limitations
- Avoirdupois ounce (28.349523125 g) differs from troy ounce (31.1034768 g, used for precious metals) — pick the right unit for context.
- Short ton (US, 2,000 lb), long ton (UK, 2,240 lb), and tonne / metric ton (1,000 kg) all share the spelling "ton" — disambiguate carefully.
- "Weight" on a scale is technically force; readings change by ~0.5% between equator and poles due to gravity, but local scales are calibrated to read mass.
- Pharmaceutical and apothecary scales use yet another set of units (grain, drachm) — not modeled here.
Conversions assume mass; scale readings on Earth approximate mass to within local-gravity precision, which is more than sufficient for everyday use.