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Free online pounds to kilograms calculator

Pounds and kilograms are two ways to measure weight. This calculator converts between them (and ounces, grams, stones, and more) instantly.

Pounds
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Kilograms
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Ounces
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Grams
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Stone
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Milligrams
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Metric ton
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Short ton
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About this calculator

How to use

  1. Enter the weight you want to convert.
  2. Select the source unit from the dropdown.
  3. All eight equivalent values update instantly.
  4. Press “Share with my numbers” to encode your inputs in the URL.

Conversion factors

All conversions use the NIST exact base: 1 pound (avoirdupois) = 0.45359237 kg

To convertMultiply by
lb → kg0.45359237
kg → lb2.204622…
lb → oz16
lb → g453.59237
lb → stone1/14
lb → mg453,592.37
kg → tonne0.001
kg → short ton1/907.18474

Worked example

Convert 165 lb:

  • kg: 165 × 0.45359237 = 74.843 kg
  • oz: 165 × 16 = 2,640 oz
  • stone: 165 / 14 = 11 stone 11 lb (11.786 stone)
  • g: 165 × 453.592 = 74,843 g

Notes

  • Source: NIST Special Publication 811, 2008 edition.
  • The avoirdupois pound is used throughout. Troy pounds and apothecary pounds are different systems and not included.
  • Milligrams are shown rounded to the nearest whole milligram.

Frequently asked

How many kilograms in a pound?
Exactly 0.45359237 kg per pound — this is the international definition adopted by the National Bureau of Standards in 1959. To convert lb to kg, multiply by 0.45359237. To convert kg to lb, divide by 0.45359237 (or multiply by ≈ 2.20462).
How many pounds in a stone?
14 pounds = 1 stone. Stone is commonly used for body weight in the UK and Ireland. 70 kg ≈ 11 stone 0 lb.
How many ounces in a pound?
16 ounces (avoirdupois) = 1 pound. This is the standard for everyday weight measurement. Note: troy ounces (used for precious metals) are different — 1 troy ounce = 31.1 g.
What is the difference between a metric ton and a short ton?
A metric ton (tonne) = 1,000 kg ≈ 2,204.6 lb. A short ton (US ton) = 2,000 lb = 907.2 kg. A long ton (UK) = 2,240 lb = 1,016 kg (not included in this calculator).
How accurate are the conversions?
The base conversion (1 lb = 0.45359237 kg) is exact by international definition. All derived conversions (oz, g, stone, etc.) flow from this exact value and are limited only by floating-point precision.