Kilograms to Troy Ounces (kg to oz t)

1 kilogram equals 32.15074657 troy ounces (rounded).

1 kilogram = 32.15074657 troy ounces

How to convert kilograms to troy ounces

To convert kilograms to troy ounces, multiply the number of kilograms by 32.15074657. The factor is rounded to 10 significant digits. To go the other way, multiply troy ounces by 0.0311034768.

troy ounces = kilograms × 32.15074657

Example: 10 kilograms = 321.5074657 troy ounces.

About these units

Kilogram (kg)

Metric (SI)Current unit

The SI base unit of mass. Since 2019 it is defined by fixing the value of the Planck constant, replacing the old platinum-iridium cylinder in Paris.

Oddly for a base unit, the kilogram began life as a derived one. In 1793 revolutionary France defined the grave as the mass of one litre of water, and a decree of 1795 then replaced it with the kilogramme, a name built from the Greek khilioi (a thousand) and gramma, a Late Latin word for a small weight. In 1799 a platinum cylinder, the Kilogramme des Archives, became the physical standard, matching a cubic decimetre of water at its densest, around 4 degrees Celsius. In 1889 the metric community adopted a platinum-iridium cylinder made in 1879, the International Prototype of the Kilogram, nicknamed Le Grand K.

The kilogram is still the only SI base unit with a prefix in its name. Because SI forbids stacked prefixes, a millionth of a kilogram is a milligram rather than a microkilogram, so every mass prefix is attached to the gram. Calibrating every national standard against one object in a vault near Paris meant that all of them drifted relative to it, so in November 2018 member states voted to tie the kilogram to a fixed value of the Planck constant. The change took effect on 20 May 2019. Day to day nothing shifted, but the definition no longer depends on a single piece of metal.

The kilogram is the reference unit for weight & mass on this site.

Sources: NIST: Kilogram introduction (SI redefinition); Wikipedia: Kilogram

Troy Ounce (oz t)

Troy & apothecaries'Current unit

Exactly 31.1034768 g (480 grains). The standard unit for precious metals; gold and silver prices are quoted per troy ounce.

Nobody is certain where troy weight got its name. The usual explanation is the fairs of Troyes in France, where English merchants traded by the early 9th century, and the word troy appears in English in 1390. An alternative theory ties it to a word for weighing by balance, though it is unsourced. Troy weights were first used in England in the 15th century and made official for gold and silver in 1527. The British Imperial troy ounce was adopted in 1824 and became the basis for US coinage through an act of Congress in 1828.

The troy ounce is exactly 31.1034768 g, or 480 grains, about 9.7 percent heavier than the ordinary avoirdupois ounce. A troy pound has only 12 ounces and is lighter than the avoirdupois pound, a mismatch that catches many first-time bullion buyers. Troy ounces remain the standard in precious-metal markets, even in countries that otherwise use SI, so gold, silver and platinum prices are all quoted per troy ounce. In the UK it is the only troy unit still permitted in trade, and only for precious metals.

1 troy ounce = 0.0311034768 kilograms (exactly).

Sources: Wikipedia: Troy ounce; Wikipedia: Ounce; NIST Guide to the SI, Appendix B.8 (mass conversions)

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