How many grams are in a troy ounce?
One troy ounce equals 31.1035 grams. The everyday ounce on food labels and bathroom scales is the avoirdupois ounce, 28.3495 grams, which makes a troy ounce about 10 percent heavier. That gap is the single most common source of confusion when people price their own gold: read a "per ounce" gold quote against a regular-ounce weight and you undervalue your metal by a tenth.
The system compounds the confusion at the pound. A troy pound is only 12 troy ounces, not 16, so a troy pound is actually lighter than a regular pound even though a troy ounce is heavier than a regular ounce. This is why serious buyers skip pounds and ounces entirely and work in grams.
| Unit | In grams | In troy ounces | Where you meet it |
|---|---|---|---|
| Troy ounce (ozt) | 31.1035 g | 1 | Gold and silver market quotes |
| Avoirdupois ounce (oz) | 28.3495 g | 0.9115 | Kitchen and postal scales |
| Pennyweight (dwt) | 1.5552 g | 0.05 (1/20) | Jewelry-trade offers |
| Gram (g) | 1 g | 0.03215 | What we weigh in, in front of you |
| Troy pound | 373.24 g | 12 | Historical texts, rarely commerce |
What is a pennyweight, and should an offer in dwt worry you?
A pennyweight (dwt) is one twentieth of a troy ounce: 1.5552 grams. It is the jewelry trade's traditional unit, and it is perfectly legitimate, but it has a side effect worth knowing: a price "per pennyweight" sounds smaller than the same price per gram sounds fair, because a pennyweight is more than one and a half grams. To compare a dwt offer to a gram offer, divide the dwt price by 1.5552. What the live market says one pennyweight and one gram of pure metal are worth right now:
| Metal | Per troy ounce | Per gram (pure) | Per pennyweight (pure) |
|---|---|---|---|
| Gold | — | — | — |
| Silver | — | — | — |
These are pure-metal values from the live feed; jewelry is alloyed, so 14K carries 58.5 percent of the pure figure and 18K carries 75 percent. The per-gram table by karat does that math live for every karat.
How many ounces in one kilogram (kg) or kilo?
A kilogram holds 32.1507 troy ounces, or 35.274 regular ounces. A kilo gold bar is therefore about 32.15 troy oz of metal, and dealers quote kilo bars in troy ounces, never kitchen ounces.
At homeHow do I convert my kitchen-scale reading?
Set the scale to grams and divide the reading by 31.1 to get troy ounces. A chain that reads 62.2 grams is almost exactly 2 troy ounces of total weight; multiply by the karat's purity to estimate the pure gold inside. A kitchen scale is fine for a ballpark, but most round to the nearest gram, and on gold a single gram of rounding is real money, which is why every offer at our counters comes off a state-certified scale reading in grams, on the counter, facing you, with the conversion done where you can check it.
Gold measurement units at a glance
Every gold measurement you will meet at a counter reduces to four units: the troy ounce (31.1035 g) for spot pricing, the gram for jewelry, the pennyweight (1.555 g) used by some buyers, and the kilo for large bars. Whatever unit an offer is quoted in, convert it back to grams and the live price and the numbers must agree.
How much is platinum per ounce of metal and per gram? Reading a platinum price chart or graph
Platinum is quoted exactly like gold: per troy ounce, with the per-gram figure found by dividing by 31.1035. Any platinum price chart or graph you look at is plotting that same per-troy-ounce number over time, and the striking thing recent charts show is platinum trading below gold, a reversal of the old assumption that platinum is automatically the dearer metal. The live figures on our platinum page update continuously, and platinum jewelry, usually stamped 950 or PLAT, is priced from that feed at every counter.
Fractional sizes: 1/100th, 1/50th, 1/8th oz and 5 oz pieces
Bullion comes in fractions as well as full ounces: 1/100th and 1/50th oz gold pieces at the tiny end, the 1/10th, 1/8th and 1/4 oz coins in the middle, and 5 oz bars and rounds above the standard ounce. The math never changes, the fraction times the live spot price, but premiums matter more as pieces shrink, because minting costs are spread over less metal. Every fractional piece is weighed and verified in front of you before the conversion is done where you can check it.
Mints we see weekly: Sunshine Minting, Scottsdale Mint, the British Royal Mint and usmint.gov
The name on a bar or coin tells you who struck it. Sunshine Minting and Scottsdale Mint are private American mints whose bars and rounds are counter staples, with Sunshine known for its MintMark SI anti-counterfeit feature. The British Royal Mint strikes the Britannia and Sovereign, and the United States Mint, usmint.gov online, strikes the Eagles and Buffalos. All of them are makers, not buyers; whoever minted your metal, it is weighed, verified and priced from the same live feed here.
Weighed in grams on a certified scale in front of you, converted at 31.1035 where you can check the math, paid the same day.
Find your nearest of our 8 storesTroy ounce FAQs
Is a troy ounce heavier than a regular ounce?
Yes, by about 10 percent: 31.1035 grams versus 28.3495 grams for the avoirdupois ounce on everyday scales. Every gold and silver quote you see is per troy ounce, so weighing on a kitchen scale and reading a market quote mixes two different ounces unless you convert.
Why are there only 12 ounces in a troy pound?
The troy system, named for the medieval French fair city of Troyes, kept the older 12-ounce pound while everyday commerce moved to 16. The result is the famous riddle: a troy ounce outweighs a regular ounce, but a troy pound of gold weighs less than a regular pound of feathers.
How many troy ounces is 100 grams?
100 divided by 31.1035 is 3.215 troy ounces. The same division works for any gram reading, which is why grams are the easiest unit to sell in: one weighing, one honest conversion, no ounce ambiguity.
Do you buy gold by the troy ounce, gram or pennyweight?
We weigh in grams on a state-certified scale in front of you and price from the live per-troy-ounce market, so the unit on the receipt never changes your money: grams times purity times the live price is the same value in any unit. Ask for the figure in dwt or troy ounces and the counter will show you the identical math.