How Many Grams in a Troy Ounce of Gold and Silver?

The question of how many grams in a troy ounce comes up the second you try to weigh gold or silver without a jeweler nearby. The answer is 31.1035 grams, and it is worth memorizing because every gold price you see online is quoted against that exact figure.

Here is the catch that trips up first-time buyers. A troy ounce is not the ounce printed on your kitchen scale. The whole troy ounce vs ounce question matters because an ounce of gold is 31.1035 grams under the troy system, while a regular ounce of flour or coffee weighs just 28.3495 grams.

How Many Grams in a Troy Ounce of Gold

Precious metals have used the troy ounce for centuries, and the figure never drifts. One troy ounce of gold is 31.1035 grams, whether the metal sits in a coin, a bar, or a wedding band. People phrase the search a dozen ways, an ounce of gold is how many grams, ounce of gold how many grams, or ounce of gold is how many grams, and the number never changes: 31.1035.

If a listing asks how many grams are in 1 troy ounce, the answer is still 31.1035. Most dealers round it to 31.1 grams in everyday talk, which is close enough for a rough valuation. Refiners and mints hold the full figure, since a fraction of a gram of gold still carries real money.

A troy ounce weighs 31.1035 grams, nearly 10 percent more than the 28.3495 grams in a standard ounce.

Troy Ounce vs Ounce: The Gram Gap Explained

The gap between the two ounces is small on paper and large in your wallet. A troy ounce is 31.1035 grams and a standard, or avoirdupois ounce, is 28.3495 grams. That leaves a difference of about 2.75 grams, so a troy ounce runs close to 10 percent heavier.

The systems split at the pound too. A troy pound holds 12 troy ounces, while the everyday avoirdupois pound holds 16 ounces. That quirk means a troy pound actually weighs less than a standard pound even though its ounce weighs more, according to published troy weight standards.

Weigh gold on a kitchen scale set to ounces and you undercount every ounce by about 2.75 grams.

Why Gold and Silver Use the Troy System

Gold, silver, platinum, and palladium are all traded by the troy ounce because global markets need one shared unit. When a screen shows gold at a spot price per ounce, that ounce is a troy ounce of gold, not the ounce on a food scale.

The habit is old. English merchants settled on troy weights in the 1400s, and by 1527 the troy ounce was Britain's official standard for gold and silver. The United States adopted the same standard in 1828, as bullion dealers still explain today.

A Short History of the Troy Ounce

The name likely traces to Troyes, a busy medieval trade fair town in France, where a standard set of weights kept cross-border deals honest. The grain, the smallest unit, stayed identical in both the troy and standard systems, which is why 480 grains and 437.5 grains describe the two ounces so precisely.

Pennyweights, Grains, and Troy Ounce to Grams

Jewelers often skip ounces entirely and weigh in pennyweights, shortened to dwt. One pennyweight is 1.5552 grams, and 20 pennyweights add up to a single troy ounce. Searching pennyweight to grams before you sell scrap gold saves you from a lowball offer.

Grains sit below pennyweights. A troy ounce holds 480 grains and a standard ounce holds 437.5 grains, yet a single grain weighs the same 0.0648 grams in either system. To move from troy ounce to grams without math, our grams to ounces converter and ounces to grams converter handle the decimals for you.

Twenty pennyweights make one troy ounce, and each pennyweight is exactly 1.5552 grams of metal.

How to Weigh Gold and Silver at Home

You do not need a jeweler's balance to get a solid estimate. A phone app that reads weight from a photo gives you a fast gram figure for a ring, a coin, or a chain. Divide that gram figure by 31.1035 and you have the troy ounce count in seconds.

The same trick works for silver flatware, scrap chains, and bullion rounds. If you are pricing metal to sell, our guide to estimating scrap metal weight walks through the same photo-first method for copper and other metals.

The Avoirdupois Ounce Trap

The costliest mistake is weighing gold on a scale set to the standard avoirdupois ounce. A seller who quotes 10 ounces on a kitchen scale is describing 283.5 grams, but 10 troy ounces should be 311 grams. That 27.5 gram gap is real gold you could lose in a single deal.

Frequently Asked Questions

How many grams are in 1 troy ounce of gold?

One troy ounce of gold is 31.1035 grams, and dealers often round it to 31.1 grams. That figure holds for any pure gold item, from a coin to a cast bar. It is the same number the global gold market uses to set the spot price.

Is a troy ounce heavier than a regular ounce?

Yes. A troy ounce is 31.1035 grams while a regular avoirdupois ounce is 28.3495 grams, so the troy ounce is about 2.75 grams or nearly 10 percent heavier. The two units share the same grain but count different totals, 480 versus 437.5.

How do I convert troy ounce to grams quickly?

Multiply the troy ounce count by 31.1035 to get grams. For a rough check, 31 grams per ounce is close enough. To skip the arithmetic on odd amounts, run the number through a grams and ounces converter and read the result directly.

How many grams in an ounce of gold jewelry?

The grams in an ounce of gold come to 31.1035 for pure metal, but most jewelry is not pure gold. A 14k piece is about 58 percent gold, so an ounce of 14k jewelry holds roughly 18 grams of actual gold with the rest made of alloy metals. Always weigh the full piece first, then adjust for karat.

Need to weigh gold, silver, or a mystery chain fast? Scale for Grams gives you an AI-powered weight estimate from a single photo in seconds, then you convert to troy ounces with one quick divide. Get the app here: iOS.