Avoirdupois Weight Conversion Calculator

The avoirdupois system is a traditional weight measurement system that became a household system of weight measurement in the 13th century. This weight system was last updated in 1959. Instead of using kilogram (kg) as the standard unit and grams as a subunit, the Avoirdupois weight system consisted of pounds and ounces.

Avoirdupois Weight Conversion Calculator
Avoirdupois Weight Conversion Results
Avoirdupois Weight Conversion Calculator. This image shows Avoirdupois Weight Conversion with associated calculations used by the Avoirdupois Weight Conversion Calculator

Introducing the Avoirdupois System and Avoirdupois Weight Conversion Calculator

It all began in the Late Middle Ages when the pound was considered a "prototype weight" comprising of 16 ounces. The definitions of pound and ounce were standardized in 1959 among countries where the pound was the standard unit of weight measurement.

Why Avoidrupois Weight System Became Famous

Earlier weight measurement systems had 10, 12 or 15 weight subdivisions. But the avoirdupois system divides into three even divisions. This imperial system of weights eventually became a standard measurement of weight among the major parts of Europe.

Since its standardization in 1959, one avoirdupois pound is equal to 0.453 kilograms.

Avoirdupois vs Troy Weight

While the avoirdupois and troy weight systems are both imperial weight systems, they have two major differences that classify them as different weight systems:

  1. In the avoirdupois weight system, one pound equals 16 ounces while the troy weight system has 12 ounces in one pound.
  2. Troy weight system is used to measure the weight of precious materials, while avoirdupois is a day-to-day weight measurement system.

When compared to troy pounds, 1 avoirdupois pound is equal to 1.22 troy pounds.

Subdivisions of Avoirdupois Weight System

The avoirdupois system is categorized into 7 subdivisions:


Also written as Drachm, this is the smallest unit of the avoirdupois weight system where 1 dram is equal to 1.772 grams or 1/16 oz.

Ounce (oz)

16 drams make up one avoirdupois ounce, denoted by oz. 1 ounce is roughly equal to 28.35 grams

Avoirdupois Pound

Denoted by lb, avoirdupois pound is equal to 453.6 grams or 16 oz.


Roughly equal to 6.350 kilograms, 1 stone comprises of 14 avoirdupois pounds.


Made up of twice the weight of one stone, a quarter weighs 12.70 kilograms and is equal to 28 avoirdupois pounds.


Sounds too hefty, doesn't it? Denoted by cwt, a hundredweight is just over 50 kgs, 50.80 kilograms to be exact and is equal to 112 avoirdupois pounds.


Also known as long ton, a ton is denoted by t and weighs about 1016 kilograms and is equal to 2240 avoirdupois pounds.

How to Use the Avoirdupois Weight Conversion Calculator

Developed by iCalculator, the avoirdupois weight conversion calculator is a simple to use online calculator that gives you accurate weight conversion numbers. All you need to do is simply type in the value you want to convert, select the given weight unit (From) and then select the unit you want the value to change into (To). The calculator will give you the results in a jiffy.

This rather simple looking math calculator can convert avoirdupois weight into various units such as dram, grain, hundredweight, ounce, pound, and ton. The grain unit given in the list is from the troy weight system.

Use of Avoirdupois in Real Life

Avoirdupois weight system's use was at its highest after the crusades, in the times of the High Middle Ages. As long distance trades through land and sea started becoming popular, avoirdupois found its requirements around ports, docks, and steelyards. Avoirdupois was seen in use wherever mass or bulk goods were sold and purchased.

As the British Empire extended towards the west, the 13 British Colonies in North America adopted this weight system. However, any changes made in the avoirdupois system in Britain were never reflected in their North American version.

While quarter is rendered almost unused in today's times, hundredweight is still a commonly used unit of measuring weight in agriculture. Earlier, drams was used for measuring gunpowder charges all across the world for black powder rifles and shotguns. But today, Grains has become the preferred unit of measuring smokeless powder and gunpowder charges across the globe.


While many units of avoirdupois may have become obsolete in today's time, we can't deny the fact that the agriculture industry still finds avoirdupois highly relevant. This rather peculiar weight system is quite fascinating, given its use in the daily life of shooters too. And when it comes to weight conversion, you simply need the avoirdupois weight conversion calculator for fastest and accurate weight conversions.

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