GoldToolkit

Troy Ounce Converter

How many grams in a troy ounce? Exactly 31.1034768. Convert between troy ounces, grams, pennyweight (dwt), kilograms, grains, and regular ounces.

1 troy ounce = 31.1034768 grams — one ounce of gold is worth $5,019.18

Gold spot: $5,019.18/troy oz · Updated Mar 15, 2026, 5:57 PM UTC

0.01oz t 100oz t

Grams

—

Troy Ounces

—

Pennyweight

—

Kilograms

—

Grains

—

Avoirdupois Ounces

—

Gold Value at Posted Spot Price

—

Assumes pure gold (24K / 999 fine) equivalent weight.

Gold Spot $5,019.18/oz
$161.37/g · $250.96/dwt
Updated Mar 15, 2026, 5:57 PM UTC

When to Use This Converter

Use this tool when you need to convert between precious-metals weight units — troy ounces, grams, pennyweight, kilograms, grains, or regular (avoirdupois) ounces. It also shows the gold value at the posted spot price for any weight you enter.

If you already know an item's weight and karat and want to calculate what it's worth, the Gold Calculator is the right tool — it factors in purity automatically.

If you want a per-gram price reference broken down by karat, use Gold Price Per Gram.

Not sure what karat your gold is? Use our Gold Hallmark & Purity Lookup to decode the stamp.

Troy Ounce vs Regular Ounce

An ounce of gold is not the same as a kitchen-scale ounce. Gold, silver, platinum, and palladium are all weighed and priced in troy ounces. Everyday goods — food, postage, body weight — use avoirdupois ounces. These are two different units with the same name, which is where the confusion starts.

A troy ounce is 31.1034768 grams. A regular avoirdupois ounce is 28.349523125 grams. The troy ounce is about 9.7% heavier. When any market, exchange, or dealer quotes gold "per ounce," they mean per troy ounce — always.

The difference extends to pounds too, though this matters less for most people. A troy pound is only 12 troy ounces (373.24g), while a regular pound is 16 avoirdupois ounces (453.59g). So a troy ounce is heavier than a regular ounce, but a troy pound is lighter than a regular pound.

Troy Ounce

31.1035g

Used for precious metals

Regular Ounce

28.3495g

Used for everything else

The Wrong-Ounce Pricing Mistake

This is the most common mistake when weighing gold at home. You put a piece on a kitchen scale, read the weight in ounces, and multiply by the spot price. The result looks right — but it's wrong by about 10%.

A kitchen scale measures in avoirdupois ounces (28.35g). The spot price is per troy ounce (31.10g). If you multiply an avoirdupois reading by the troy-ounce spot price, you're paying a troy-ounce price for less than a troy ounce of metal. The number you get is too high.

Worked Example — How the Wrong Ounce Overstates Value

Your kitchen scale reads 1 ounce of gold. You think you have 1 troy ounce — but you actually have only 0.9115 troy ounces (28.35g instead of 31.10g).

You assume: $5,019.18 (too high)

Actual value: 0.9115 × $5,019.18 = $4,574.77

You've overstated the value by $444.41 — about 9.7%. Weigh in grams instead to avoid this entirely.

The simplest way to avoid this: weigh in grams. Every jewelry scale and most kitchen scales can display grams, and grams are unambiguous — there's only one kind of gram. Enter the gram weight into our Gold Calculator and it handles the rest.

Pennyweight (DWT) Explained

A pennyweight is 1/20 of a troy ounce, or exactly 1.55517384 grams. The abbreviation dwt stands for "denarius weight" — the "d" from the Latin denarius (an old silver coin), "wt" for weight.

Pennyweight is widely used in the U.S. jewelry trade. Many independent jewelers, gold buyers, and pawn shops quote prices per pennyweight rather than per gram. If you're getting offers from a gold buyer, knowing the dwt-to-gram conversion helps you compare quotes that use different units.

1 DWT

1.5552g

1 Troy Oz

20dwt

1 Gram

0.6430dwt

Pure Gold / DWT

$250.96

For a full price breakdown by karat and unit (grams, dwt, and troy ounces), see Gold Price Per Gram.

Weight Conversion Reference Table

From Grams Troy Oz
1 Troy Ounce 31.1035 1.0000
1 Gram 1.0000 0.0322
1 Kilogram 1000.0000 32.1507
1 Pennyweight 1.5552 0.0500
1 Grain 0.0648 0.0021
1 Avdp. Ounce 28.3495 0.9115

All underlying conversion constants are exact definitions. Table values are rounded to four decimal places. To calculate the dollar value of a specific gold item by weight and karat, use the Gold Calculator.

Frequently Asked Questions

How many grams are in an ounce of gold?
An ounce of gold is a troy ounce — exactly 31.1034768 grams. This is not the same as a kitchen-scale ounce (28.35g). At the posted spot price of $5,019.18 per troy ounce, one gram of pure gold is worth $161.37. When gold is quoted at a price "per ounce," it always means per troy ounce.
What is the difference between a troy ounce and a regular ounce?
A troy ounce is 31.1035 grams. A regular (avoirdupois) ounce is 28.3495 grams — about 9.7% lighter. The troy system has been used for precious metals for centuries, while the avoirdupois system is used for everyday goods. The two systems also define "pound" differently: a troy pound is 12 troy ounces (373.24g), while an avoirdupois pound is 16 regular ounces (453.59g).
What is a pennyweight (dwt)?
A pennyweight (abbreviated dwt) equals exactly 1/20 of a troy ounce, or 1.55517384 grams. It's the standard unit for weighing and pricing gold in the U.S. jewelry trade. At the posted spot price, one pennyweight of pure gold is worth $250.96. If a jeweler quotes a price "per dwt," use the converter above to see what that translates to in grams or troy ounces.
Why does it matter whether I weigh gold in troy ounces or regular ounces?
Using the wrong ounce creates a pricing error of about 9.7%. If you weigh gold on a kitchen scale in regular ounces and multiply by the troy-ounce spot price, you'll overstate the value by roughly $444.41 per ounce. Always weigh gold in grams or troy ounces. Our Gold Calculator handles unit conversion automatically.
How many pennyweights are in a troy ounce?
Exactly 20. One pennyweight (dwt) = 1.55517384 grams, and 20 dwt = 31.1034768 grams = 1 troy ounce. Pennyweight is still the preferred unit for gold transactions in much of the U.S. jewelry industry, particularly among independent jewelers and gold buyers.
Why are precious metals weighed in troy ounces instead of regular ounces?
The troy system is historically associated with the trade fairs of Troyes, France, and was adopted into English law by the early 16th century. It has been used for gold and silver pricing ever since. The system persists because international commodity markets, mints, and refineries all use it — changing would require global coordination across every exchange, vault, and assay office.
What is a grain?
A grain equals exactly 0.06479891 grams. There are 480 grains in a troy ounce and 437.5 grains in an avoirdupois ounce. The grain is the one unit that is identical in both the troy and avoirdupois systems. It's rarely used in gold trading today but still appears in ammunition specifications and occasionally in legacy pharmaceutical dosing.
How do I convert dwt to grams?
Multiply the number of pennyweight by 1.55517384. For example, 10 dwt = 15.5517 grams. To go the other way, divide grams by 1.55517384. The converter above does this automatically — enter a value in either unit and all other conversions update instantly.
Is a troy ounce the same worldwide?
Yes. A troy ounce is defined as exactly 31.1034768 grams everywhere (NIST reference). The London Bullion Market Association (LBMA), COMEX, the Shanghai Gold Exchange, and every major mint use this same definition. When any exchange quotes gold per ounce, it means this exact weight.

Related Calculators

Au

Gold Value

Calculate the melt value of gold by weight and karat
$

Scrap Gold

Calculate total melt value of multiple gold items at once
g

Price Per Gram

Gold price per gram for every common karat
K

Purity Lookup

Decode gold hallmark stamps and convert between karat, percentage, and fineness

Transparent Formula

Every calculation uses the standard melt value formula. No hidden fees or markups.

Data Source

Spot-price data is provided via metals.dev. Last updated Mar 15, 2026, 5:57 PM UTC. Methodology

No Account Required

All tools are free with no sign-up, no tracking cookies, and no personal data collection.