Avoirdupois Weight Conversion Calculator

Avoirdupois Weight Conversion Calculator

Convert between traditional and metric weight units

Weight Converter

About Avoirdupois Weight System

Historical Background

The avoirdupois weight system is a traditional system of weights that originated in the 13th century and was standardized in the British Weights and Measures Act of 1824. It is still widely used in the United States and partly in the United Kingdom for everyday weight measurements.

Avoirdupois Weight Units

Unit Abbreviation Equivalent in Grains Modern Equivalent
Grain gr 1 64.79891 mg
Dram dr 27.34375 1.7718451953125 g
Ounce oz 437.5 28.349523125 g
Pound lb 7,000 453.59237 g
Stone st 98,000 6.35029318 kg
Quarter qtr 196,000 12.70058636 kg
Hundredweight cwt 784,000 50.80234544 kg
Long Ton ton 15,680,000 1016.0469088 kg
Short Ton sh_ton 14,000,000 907.18474 kg

About Weight Conversions

Understanding Avoirdupois Weight

The avoirdupois system is a traditional weight measurement system that originated in the 13th century. It is the everyday weight system used in the United States and partially in the United Kingdom for many items.

Key Features

  • Based on the pound of 7,000 grains
  • Used primarily for weighing bulk dry commodities
  • Different from troy and apothecaries' systems, which use a pound of 5,760 grains
  • Includes units like drams, ounces, pounds, stones, quarters, hundredweights, and tons

Common Usage

While many countries have officially adopted the metric system, avoirdupois units are still commonly used in:

  • Body weight measurement (pounds and stones)
  • Food packaging and recipes
  • Agricultural products
  • Construction materials
  • Shipping and logistics

Avoirdupois vs. Troy Weight

It's important not to confuse avoirdupois weight with troy weight, which is used for precious metals:

  • A troy ounce (31.1035 g) is heavier than an avoirdupois ounce (28.3495 g)
  • A troy pound (373.242 g) is lighter than an avoirdupois pound (453.592 g)
  • Troy weight uses 12 ounces to the pound, while avoirdupois uses 16 ounces

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Conversion History

No conversion history yet.

Conversion Examples

Avoirdupois Conversions

  • 1 pound (lb) = 16 ounces (oz)
  • 1 ounce (oz) = 16 drams (dr)
  • 1 stone (st) = 14 pounds (lb)
  • 1 hundredweight (cwt) = 112 pounds (lb)
  • 1 ton = 2,240 pounds (lb)
  • 1 short ton = 2,000 pounds (lb)

Metric Equivalents

  • 1 pound (lb) ≈ 453.59 grams (g)
  • 1 ounce (oz) ≈ 28.35 grams (g)
  • 1 kilogram (kg) ≈ 2.205 pounds (lb)
  • 1 gram (g) ≈ 0.035 ounces (oz)

Practical Examples

  • A stick of butter is typically 4 ounces (113 grams)
  • A bag of flour is often 5 pounds (2.27 kilograms)
  • A person weighing 70 kilograms weighs about 154 pounds
  • A quarter pound hamburger is 4 ounces or 113 grams
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