How many kg is 1 pound?

One pound equals exactly 0.45359237 kilograms. This is a precisely defined value from the international yard and pound agreement. For quick mental maths, dividing pounds by 2.2 gives a close approximation in kilograms.

Why do Americans use pounds instead of kilograms?

The United States is one of only three countries (along with Myanmar and Liberia) that has not officially adopted the metric system. The US Customary System evolved from British imperial units, and despite various metrication initiatives since the 1970s, pounds, ounces, and other imperial measures remain standard for everyday use.

How do I convert lbs to stone and pounds?

Divide the total pounds by 14 to get stone. The whole number is the stone, and the remainder is the extra pounds. For example, 165 lbs / 14 = 11 stone with 11 lbs remaining, so 165 lbs = 11 stone 11 lbs. This converter shows both kg and stone results.

Pounds to Kilograms Converter

Convert pounds to kilograms and kilograms to pounds

Published by UltraCalculatorsLast reviewed: 1 Apr 2026v1.0Report an issue

Pounds and kilograms are the world's two main weight measurement systems, and converting from pounds to kilograms is something that comes up surprisingly often in British life. Although the UK officially uses the metric system, pounds remain familiar through American media, imported products, and legacy usage. When an American fitness app tells you to lift 135 lbs, or a US recipe calls for 2 lbs of chicken, knowing the kilogram equivalent is essential. One pound equals exactly 0.45359237 kilograms. This precise definition was established by the international yard and pound agreement between the US, UK, Canada, Australia, New Zealand, and South Africa in 1959. In practice, dividing the number of pounds by 2.2 gives a quick approximation that is good enough for most everyday purposes. This converter handles both directions and also shows the stone equivalent, which is particularly useful for UK users who think about body weight in stone. Whether you are interpreting US product weights, converting gym plates, or translating a recipe, the tool provides an instant, precise answer.

How to Use This Calculator

To use the pounds to kilograms converter: 1. Select the conversion direction. Choose "Pounds to Kilograms" if you have a weight in lbs. Choose "Kilograms to Pounds" for the reverse. 2. For lbs to kg: Enter the weight in pounds. The converter shows kilograms, the stone and pounds equivalent, and the total in grams. 3. For kg to lbs: Enter the weight in kilograms. The converter shows pounds with the stone equivalent. 4. Results update instantly and are precise to four decimal places.

How It Works

The conversion uses the exact definition: 1 lb = 0.453592 kg. Pounds to Kilograms: kg = lbs x 0.453592 Stone = lbs / 14 (whole number) Remaining lbs = lbs mod 14 Example: 150 lbs = 150 x 0.453592 = 68.039 kg = 10 st 10 lbs Kilograms to Pounds: lbs = kg x 2.20462 Stone = total lbs / 14 Example: 80 kg = 80 x 2.20462 = 176.37 lbs = 12 st 8.4 lbs Quick mental shortcut: halve the pounds, then subtract 10% of that result. For example, 200 lbs: half = 100, minus 10% (10) = 90 kg (actual: 90.7 kg).

Worked Examples

Example 1: Converting US dumbbell weights for a home gym

Inputs: Pounds: 45. Direction: lbs to kg.

Kilograms = 45 x 0.453592 = 20.412 kg.
Stone: 45 / 14 = 3 st 3 lbs.
Grams: 20,412.

Result: 45 lbs equals 20.4 kg. A standard Olympic plate in the US (45 lbs) is roughly equivalent to a 20 kg plate in the UK.

Example 2: Understanding a US weight loss story

Inputs: Pounds: 220. Then: Pounds: 175.

Starting: 220 x 0.453592 = 99.79 kg (15 st 10 lbs).
Current: 175 x 0.453592 = 79.38 kg (12 st 7 lbs).
Lost: 99.79 - 79.38 = 20.41 kg (3 st 3 lbs).

Result: Losing 45 lbs (220 to 175) equals a loss of 20.4 kg or 3 stone 3 pounds.

Example 3: Converting luggage weight for a US airline

Inputs: Kilograms: 23. Direction: kg to lbs.

Pounds = 23 x 2.20462 = 50.706 lbs.
Stone: 50.706 / 14 = 3 st 8.7 lbs.

Result: 23 kg equals 50.7 lbs. Most US airlines allow 50 lbs for checked bags, so 23 kg is just over the limit.

Common conversions: 100 lbs = 45.4 kg = 7 st 2 lbs, 125 lbs = 56.7 kg = 8 st 13 lbs, 150 lbs = 68.0 kg = 10 st 10 lbs, 175 lbs = 79.4 kg = 12 st 7 lbs, 200 lbs = 90.7 kg = 14 st 4 lbs, 250 lbs = 113.4 kg = 17 st 12 lbs. One pound is 16 ounces or approximately 454 grams.