A pennyweight (dwt) is a unit of

mass Mass is an Intrinsic and extrinsic properties, intrinsic property of a physical body, body. It was traditionally believed to be related to the physical quantity, quantity of matter in a body, until the discovery of the atom and particle physi ...

equal to 24

grains A grain is a small, hard, dry fruit ( caryopsis) – with or without an attached hull layer – harvested for human or animal consumption. A grain crop is a grain-producing plant. The two main types of commercial grain crops are cereals and le ...

, of a

troy ounce Troy weight is a system of units of mass that originated in the Kingdom of England in the 15th century and is primarily used in the precious metals industry. The troy weight units are the grain, the pennyweight (24 grains), the troy ounce (20 p ...

, of a

troy Troy (/; ; ) or Ilion (; ) was an ancient city located in present-day Hisarlik, Turkey. It is best known as the setting for the Greek mythology, Greek myth of the Trojan War. The archaeological site is open to the public as a tourist destina ...

pound,

avoirdupois ounce The ounce () is any of several different units of mass, weight, or volume and is derived almost unchanged from the , an Ancient Roman unit of measurement. The avoirdupois ounce (exactly ) is avoirdupois pound; this is the United States cu ...

and exactly 1.55517384

gram The gram (originally gramme; SI unit symbol g) is a Physical unit, unit of mass in the International System of Units (SI) equal to one thousandth of a kilogram. Originally defined in 1795 as "the absolute Mass versus weight, weight of a volume ...

s. It is abbreviated dwt, ''d'' standing for ''

denarius The ''denarius'' (; : ''dēnāriī'', ) was the standard Ancient Rome, Roman silver coin from its introduction in the Second Punic War to the reign of Gordian III (AD 238–244), when it was gradually replaced by the ''antoninianus''. It cont ...

'' (an ancient Roman coin), and later used as the symbol of an old British penny (see

£sd file:Guildhall Museum Collection- Drusilla Dunford Money Table Sampler 3304.JPG, A Sampler (needlework), sampler in the Rochester Guildhall, Guildhall Museum of Rochester, Medway, Rochester illustrates the conversion between pence and shillings ...

History

In the Middle Ages, an

English penny The English penny (plural "pence"), originally a coin of pure silver, was introduced by King Offa of Mercia. These coins were similar in size and weight to the continental '' deniers'' of the period and to the Anglo-Saxon sceats which had p ...

's weight was literally, as well as monetarily, of an ounce and of a pound of

sterling silver Sterling silver is an alloy composed mass fraction (chemistry), by weight of 92.5% silver and 7.5% other metals, usually copper. The sterling silver silver standards, standard has a minimum millesimal fineness of 925. ''Fineness, Fine silver'' ...

. At that time, the pound unit in use in England was the

Tower pound The pound or pound-mass is a unit of mass used in both the British imperial and United States customary systems of measurement. Various definitions have been used; the most common today is the international avoirdupois pound, which is le ...

, equal to 7,680 Tower grains (also known as wheat grains). The medieval English pennyweight was thus equal to 32 Tower grains. When Troy weights replaced Tower weights in 1527, the Troy weights were defined in such a way that the old Tower pound came out to exactly 5,400 Troy grains (also known as barleycorns), the Tower pennyweight Troy grains (and thus approximately 1.46 grams). After 1527, the English pennyweight was the Troy pennyweight. of 24 Troy grains. Thus the Troy pound, ounce, and pennyweight, with their definitions given in terms of the Troy grain instead of in terms of the Tower grain, were or 6.667% more than the Tower equivalents.

Usage

The troy pound and the pennyweight lost their official status in the

United Kingdom The United Kingdom of Great Britain and Northern Ireland, commonly known as the United Kingdom (UK) or Britain, is a country in Northwestern Europe, off the coast of European mainland, the continental mainland. It comprises England, Scotlan ...

in the

Weights and Measures Act A weights and measures act is a kind of legislative act found in many jurisdictions establishing technical standards for weights and measures. Notable acts of this type include: * Various Weights and Measures Acts (UK) or the various legislative ...

of 1878; only the troy ounce and its decimal subdivisions remained official. The troy ounce enjoys a specific legal exemption from

metrication Metrication or metrification is the act or process of converting to the metric system of measurement. All over the world, countries have transitioned from local and traditional Unit of measurement, units of measurement to the metric system. This ...

in the UK. The pennyweight is the common weight used in the valuation and measurement of precious metals. Jewellers use the pennyweight in calculating the amount and cost of precious metals used in fabricating or casting jewellery. Similarly, dentists and dental labs still use the pennyweight as the measure of precious metals in dental crowns and inlays. Pennyweight and grains are still used to weigh

gooseberries Gooseberry ( or (American and northern British) or (southern British)) is a common name for many species of ''Ribes'' (which also includes currants), as well as a large number of plants of similar appearance, and also several unrelated pl ...

in competitions in

Cheshire Cheshire ( ) is a Ceremonial counties of England, ceremonial county in North West England. It is bordered by Merseyside to the north-west, Greater Manchester to the north-east, Derbyshire to the east, Staffordshire to the south-east, and Shrop ...

, northwest UK. Over the

Pennines The Pennines (), also known as the Pennine Chain or Pennine Hills, are a range of highland, uplands mainly located in Northern England. Commonly described as the "Vertebral column, backbone of England" because of its length and position, the ra ...

Yorkshire Yorkshire ( ) is an area of Northern England which was History of Yorkshire, historically a county. Despite no longer being used for administration, Yorkshire retains a strong regional identity. The county was named after its county town, the ...

the alternative drams and grains measurement has been used since a new set of scales was purchased by the Egton Bridge Old Gooseberry Society in 1937. As of 2018, the world record for the heaviest gooseberry of () was held by Kelvin Archer of Cheshire. The most common abbreviation for pennyweight is ''dwt''; ''d'', for the Roman ''

'', was the abbreviation for ''penny'' before Decimalisation of the British monetary system. Alternate abbreviations are ''pwt'' and ''PW''.

Uses unrelated to weight

Although the abbreviations are the same, the pennyweight bears no relation to the weight of the American penny nail. That name is derived from the price for a hundred nails in 15th century

England England is a Countries of the United Kingdom, country that is part of the United Kingdom. It is located on the island of Great Britain, of which it covers about 62%, and List of islands of England, more than 100 smaller adjacent islands. It ...

: the larger the nail, the higher the cost per hundred. The pennyweight also bears no relation to the weight of the American "

penny A penny is a coin (: pennies) or a unit of currency (: pence) in various countries. Borrowed from the Carolingian denarius (hence its former abbreviation d.), it is usually the smallest denomination within a currency system. At present, it is ...

" (1 cent) coin, which weighs 2.5 g (for those minted after 1982).

Conversion

References

{{Reflist Obsolete units of measurement Units of mass Customary units of measurement in the United States