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Free health tool

Kilograms to pounds converter

Convert an existing weight value between kilograms and pounds using the exact international pound definition, without interpreting the weight.

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Calculate your result

Enter one weight or mass value. Do not add thousands separators; use a full stop when a comma with three following digits could be ambiguous.

Accepted range: 0 to 1000 kg

Your result will appear here

Nothing is saved or added to the URL.

What this result means

Choose the unit you have and enter one weight value. The converter changes kg to lb or lb to kg using the exact definition 1 lb = 0.45359237 kg. It converts the unit only and does not interpret the weight. [1][2]

What kg and lb mean

The kilogram (kg) is the SI unit of mass. The international avoirdupois pound (lb) is defined as exactly 0.45359237 kilogram. [1][2]

Why the factor is 0.45359237

NIST lists one international avoirdupois pound as exactly 0.45359237 kg. Multiply pounds by that value for kilograms; divide kilograms by it for pounds. [1][2]

This uses the everyday pound

The international avoirdupois pound is used for body weight, gym equipment and most everyday mass records. It is not a troy pound and not pound-force. [2]

Why converted displays may differ slightly

A scale or record may already round its number. This tool calculates from the value you enter and rounds the converted display to two decimal places. [1]

What this conversion cannot tell you

A converted unit contains the same underlying weight information as the original. It cannot tell you whether the weight is healthy, what target to use, or how to calculate a medication or nutrition dose.

Formula and assumptions

Formula
lb = kg ÷ 0.45359237. kg = lb × 0.45359237. [1][2]
Version
International avoirdupois pound and kilogram conversion, nist-international-pound-kg-v1
Rounding
Calculate with the exact international definition 1 lb = 0.45359237 kg and round once for display to two decimal places.
Worked example
For 70 kg: 70 ÷ 0.45359237 = 154.3236 lb, displayed as 154.32 lb. For 154.32 lb: 154.32 × 0.45359237 = 69.9984 kg, displayed as 70.00 kg. [1][2]

Who this is for — and when not to use it

Intended use

Neutral conversion of one existing body-weight, gym-weight or other everyday mass value between kilograms and international avoirdupois pounds.

Not intended for

This tool does not judge body weight, calculate BMI, set a target, estimate weight change, calculate medication or nutrition doses, or validate a scale or equipment limit.

Exclusions

  • Body-weight classification or diagnosis
  • BMI, body-fat or ideal-weight calculations
  • Medication, nutrition or supplement dosing
  • Weight-loss targets or predictions
  • Scale calibration or equipment safety decisions

Evidence sources

  1. 1. NIST Special Publication 1020: Guide for Labeling Consumer Package by Weight, Volume, Count, or Measure — National Institute of Standards and Technology. Accessed Aug 9, 2026.
  2. 2. NIST Handbook 44, Appendix C — General Tables of Units of Measurement — National Institute of Standards and Technology. Accessed Aug 9, 2026.