Pounds to Kilograms Explained
The international pound (lb) is defined as exactly 0.45359237 kilograms. This precise definition, agreed upon in 1959 by English-speaking countries, ensures exact and consistent conversion between the two units.
Pounds are widely used in the United States for body weight, food, and many everyday measurements. In Ireland, pounds are sometimes combined with stones for expressing body weight — 14 pounds make one stone. Knowing how to convert between these systems is useful when reading US health and fitness content, interpreting food labels, or calculating luggage weight for US-bound flights.
Common references: 100 lb = 45.36 kg (about 7 stone 2 lb); 150 lb = 68.04 kg (10 stone 10 lb); 200 lb = 90.72 kg (14 stone 4 lb).
Formula
To convert pounds to kilograms: kg = lb × 0.453592. For stones: divide pounds by 14 — the whole number is stones, the remainder is pounds.
Common Pounds to Kilograms Conversions
- 1 lb = 0.454 kg
- 5 lb = 2.268 kg
- 10 lb = 4.536 kg
- 50 lb = 22.680 kg
- 100 lb = 45.359 kg
- 150 lb = 68.039 kg
- 200 lb = 90.718 kg
Pounds in Everyday Life
- Body weight — US medical records, gym equipment, and scales use pounds; European records use kilograms
- Airline luggage — many US carriers set baggage limits in pounds (e.g. 50 lb = 22.68 kg)
- Food and cooking — US recipes frequently use pounds and ounces; European recipes use grams
- Fitness and weightlifting — barbells and dumbbells are often labelled in both lb and kg
- Newborn weight — some hospitals record birth weight in pounds and ounces alongside kilograms
Related Calculators
- Kilograms to Pounds — Convert kg to lb and stones & pounds.
- Kilograms to Stones — Convert kg to stones and pounds.
- Stones to Kilograms — Convert stones and pounds to kg.