Weight Unit Converter

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Weight Conversion for All Needs

Convert between metric and imperial weight units with ease. Our weight converter supports all common units including kilograms, grams, pounds, ounces, stones, and specialized units like metric tons and atomic mass units. All conversions are based on the ISO 80000 standards for maximum accuracy.

Common Weight Conversions

  • 1 pound = 0.45359237 kilograms (exact)
  • 1 kilogram = 2.20462262 pounds
  • 1 ounce = 28.3495231 grams
  • 1 stone = 6.35029318 kilograms
  • 1 ton (US) = 907.18474 kilograms
  • 1 ton (UK) = 1016.0469088 kilograms

Weight Units and Standards

The kilogram (kg) is the SI base unit for mass, defined by the Planck constant which is exactly 6.62607015×10−34 joule seconds.

  • Milligram (mg): 10-3 grams
  • Gram (g): 10-3 kilograms
  • Kilogram (kg): Base SI unit
  • Metric ton (t): 103 kilograms

Understanding Weight Measurements

Weight (more accurately, mass) is a fundamental measure of the amount of matter in an object. The scientific distinction between mass and weight is that mass is an intrinsic property of matter, while weight is the force exerted on mass due to gravity. In everyday use, however, the terms are often used interchangeably.

Precision: 15 decimal places
Standard: ISO 80000-4:2019

Weight Units in Different Systems

Metric Weight Units

The metric system uses the kilogram as its base unit with standard prefixes:

  • Metric ton (t): 1,000 kilograms
  • Kilogram (kg): Base unit
  • Gram (g): 0.001 kilogram
  • Milligram (mg): 0.000001 kilogram
  • Microgram (μg): 0.000000001 kilogram

Imperial Weight Units

The imperial system uses different conversion factors:

  • Ton (long): 2,240 pounds (UK)
  • Ton (short): 2,000 pounds (US)
  • Stone: 14 pounds
  • Pound (lb): 16 ounces
  • Ounce (oz): 16 drams
  • Grain: 1/7000 of a pound