Convert Pound to Kilogram
Convert pounds to kilograms instantly. 1 pound = 0.45359237 kilogram — use the live calculator, the exact formula, a conversion table and worked examples. Also check the Kilogram to Pound converter for the reverse conversion.
Units explained
Pound
The pound (lb) is a unit of mass equal to exactly 0.45359237 kilogram.
From Latin 'libra pondo' (a pound by weight); the symbol lb comes from 'libra'.
The primary weight unit in the United States and informally in the UK.
The international avoirdupois pound was fixed in the 1959 yard-and-pound agreement.
Kilogram
The kilogram (kg) is the SI base unit of mass, defined by fixing the Planck constant h at 6.62607015E-34 J s.
From Greek 'khilioi' (thousand) plus 'gramma' (small weight).
The worldwide base unit of mass in science, commerce, and everyday life.
Adopted in 1795; redefined through the Planck constant on 20 May 2019.
Pound to Kilogram conversion formula
The relationship between pounds and kilograms:
To convert pounds to kilograms, multiply the value in pounds by 0.45359237. To reverse, multiply kilograms by 2.2046226218.
How to use this converter
Type a value into the calculator. The result in kilograms updates as you type. Tap a quick value, copy the result with one click, or use the swap arrow to jump straight to the Kilogram to Pound converter for the reverse direction.
Step-by-step: convert pounds to kilograms
- Write down the value in pounds (lb).
- Multiply that value by the factor 0.45359237.
- The product is the equivalent value in kilograms (kg).
- To reverse, multiply the kilogram value by 2.2046226218.
Worked examples
Example 1 — Convert 1 lb to kg:
1 × 0.45359237 = 0.45359237 kg
Example 2 — Convert 100 lb to kg:
100 × 0.45359237 = 45.359237 kg
Real-world example — Reference scenario in case of fallback
Conversion between human-scale length units is the everyday workflow of architecture, athletics, and apparel design — three of the most common contexts that span metric and imperial systems.
1 lb × 0.45359237 = 0.45359237 kg
Real-world example — Adult height conversion
A 1.8-pound-tall person measures a value in kilograms that converts the height to the unit favoured by American forms, schools, or driver's licences. This is daily routine for anyone living between metric and imperial systems.
1.8 lb × 0.45359237 = 0.816466266 kg
Real-world example — Fabric purchase length
Two pounds of fabric equals a value in kilograms essential for tailors and textile buyers sourcing material from international suppliers that quote in different units.
2 lb × 0.45359237 = 0.90718474 kg
Pound to Kilogram conversion table
Standard reference values for converting pounds to kilograms:
| Pound [lb] | Kilogram [kg] |
|---|---|
| 0.01 | 0.0045359237 |
| 0.1 | 0.045359237 |
| 1 | 0.45359237 |
| 2 | 0.90718474 |
| 3 | 1.36077711 |
| 4 | 1.81436948 |
| 5 | 2.26796185 |
| 10 | 4.5359237 |
| 20 | 9.0718474 |
| 30 | 13.6077711 |
| 40 | 18.1436948 |
| 50 | 22.6796185 |
| 100 | 45.359237 |
| 500 | 226.796185 |
| 1000 | 453.59237 |
Frequently asked questions
How many kilograms is 1 pound?
How do I convert pounds to kilograms?
How do I convert kilograms back to pounds?
How many kilograms is 100 pounds?
Popular weight unit conversions
Convert Pound to other weight units
Show all Pound conversions
Metric / SI (18 units)
Avoirdupois (14 units)
Troy & Apothecary (10 units)
Indian / South Asian (6 units)
Scientific / Atomic (9 units)
Astronomical (4 units)
Biblical / Ancient (14 units)
Sources & references
Conversion factor (1 lb = 0.45359237 kg) verified against the following authoritative sources:
- BIPM — The International System of Units (SI Brochure 9th ed.)
Official BIPM publication defining the seven SI base units (including the meter) and the rules for their use. The global authority on units of measurement.
- NIST — Guide to the SI
US National Institute of Standards and Technology reference covering the SI base and derived units with definitions and usage rules for US technical practice.
- NIST Special Publication 811 — Guide for the Use of the International System of Units
Detailed NIST guide covering exact conversion factors between SI and US customary units along with formatting and rounding conventions.
- NIST — Refinement of values for the yard and pound (Federal Register 1959)
The treaty (signed by US
- International Astronomical Union — System of Astronomical Constants
The IAU defines astronomical units including the AU (149597870700 m exactly) light-year and parsec used in astronomy and astrophysics.