Why is the Troy Ounce heavier than a regular ounce?

The Troy Ounce is a medieval unit of measurement from Troyes, France. It was specifically designed to standardize the trade of precious metals, whereas the Avoirdupois system was designed for trade of other goods like wool and grain.

Is 18k gold worth less than 24k gold?

Per gram, yes. Since 18k gold contains only 75% gold, its value is exactly 75% of the 24k gold price. However, 18k is much more durable for jewelry.

How do I calculate the price of 1 gram of gold?

To find the price per gram, take the Current Global Gold Ounce Price and divide it by 31.1035. Example: If gold is $5000/oz, then 1 gram of 24k gold is roughly $160.75.

Does the Ounce unit change for Silver or Platinum?

No. All precious metals are measured using the same 31.1035g Troy Ounce standard.

Gold Ounce to Grams: The Ultimate Conversion Guide

Krishna

Published:2026-02-04

Updated:2026-02-08

Read time:4 Minutes

If you are considering investing in gold and would like to know how many grams of gold in different karats correspond to one troy ounce in the global gold market, this article provides a clear and precise explanation.

If you are looking to invest in precious metals, understanding the Troy Ounce is essential. Global gold prices are always quoted in ounces, but most physical gold, like jewelry or coins, is weighed in grams.

Quick Summary:
• 1 Troy Ounce of 24k Gold = 31.1035 Grams
• 1 Troy Ounce equivalent in 18k Gold = 41.4713 Grams

What is a Gold Ounce? Troy Ounce vs. Regular Ounce

A gold ounce is a standard unit of weight used to measure precious metals such as gold, silver, and platinum.

The precious metals market uses the Troy Ounce. Using the wrong unit can result in a 9% loss in weight calculation.

Unit Type	Weight in Grams	Common Use
Troy Ounce	31.1034768 g	Gold, Silver, Platinum
Regular Ounce	28.3495 g	Groceries, Post, Cooking

Key facts about a gold ounce:

1 troy ounce of gold = exactly 31.1034768 grams
It is based on pure gold (24-karat, 99.99% purity)
Global gold prices are always quoted per troy ounce

How Many Grams of 18k/24k Gold is One Ounce?

To understand this, we have to look at purity.

24-Karat (24k): 99.9% pure gold.

18-Karat (18k): 75% gold and 25% alloy metals like copper or silver.

Because 18k gold is less pure, you need more total mass to equal the amount of pure gold found in one Troy Ounce.

The Conversion Formulas

If you have Gold price per ounce and want to determine the weight equivalent in different gold karats, use the following formulas.

24K Gold (Pure Gold)

24K gold is 100% pure, so its weight corresponds directly to the gold ounce.

Weight of 24K gold = ounce amount × 31.103

Pure gold content (g) = Total weight of 24K gold × 1.00

22K Gold

22K gold contains 22/24 (91.67%) pure gold.

Weight of 22K gold = (ounce amount × 31.103) ÷ 0.9167

Pure gold content (g) = Total weight of 22K gold × 0.9167

18K Gold

18K gold contains 18/24 (75%) pure gold.

Weight of 18K gold = (ounce amount × 31.103) ÷ 0.75

Pure gold content (g) = Total weight of 18K gold × 0.75

Unit	Equivalent
One ounce of 24-karat gold	31.103 grams of 24-karat gold
One ounce of 24-karat gold	41.47 grams of 18-karat gold
One gram of 24-karat gold	1.33 grams of 18-karat gold

Quick Reference Conversion Table

Use this table to quickly convert Troy Ounces into grams for both pure 24k investment gold and 18k jewelry gold.

Gold Ounces (oz t)	24-Karat Gold (Grams)	18-Karat Gold (Grams)
1 oz	31.10 g	41.47 g
2 oz	62.21 g	82.94 g
5 oz	155.52 g	207.36 g
10 oz	311.03 g	414.71 g
50 oz	1,555.17 g	2,073.57 g

Calculating the Price of 18K & 24K Gold Using the Global Gold Ounce Price

To calculate the price of gold using the global ounce price, you need to follow these steps:

Price of 1 gram of 24K gold:
(Global gold ounce price × local exchange rate) ÷ 31.1035

Price of 1 gram of 18K gold:
Price of 1 gram of 24K gold × 0.75

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