How many grams are in a troy ounce?

One troy ounce equals exactly 31.1034768 grams. This differs from an avoirdupois ounce, which is approximately 28.3495 grams.

What is a pennyweight?

A pennyweight (dwt) is a unit of mass equal to 1/20 of a troy ounce, or approximately 1.5552 grams. It is commonly used in the jewelry trade for pricing gold and silver.

Why do precious metals use troy ounces instead of regular ounces?

Troy weight is a system used historically for precious metals and gemstones. One troy ounce (31.10 g) is heavier than one avoirdupois ounce (28.35 g), so always confirm which system a price quote uses.

How many grains are in a troy ounce?

One troy ounce equals exactly 480 grains. The grain is the smallest traditional unit of mass in the troy system and is also used in ballistics and pharmacy.

Is the gram the same in both systems?

Yes. The gram is an SI unit and does not vary between the troy and avoirdupois systems. Only the ounce differs between them.

How much is 1 troy ounce of gold worth?

Gold is priced per troy ounce (31.1035 g), so 1 troy oz of gold is worth the live spot price — multiply the per-gram price by 31.1035, or the per-troy-oz spot directly. This tool converts the weight; check a live feed for the current price.

Troy Ounce Converter

Name: Troy Ounce Converter
Availability: InStock
Author: Nham Vu

Convert troy ounces to grams, avoirdupois ounces, pennyweights, and grains instantly in your browser.

Enter a Weight

Type in any field to convert all units simultaneously.

Troy Ounce (ozt)

Gram (g)

Avoirdupois Ounce (oz)

Pennyweight (dwt)

Grain (gr)

Conversion Results

Enter a value on the left to see conversions.

Reference Factors

Unit	= 1 Troy oz
Grams	31.1034768
Avoirdupois oz	1.09714286
Pennyweights	20
Grains	480

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Summary

Convert troy ounces to grams, avoirdupois ounces, pennyweights, and grains instantly in your browser.

How it works

Enter a value in any unit field — troy ounces, grams, avoirdupois ounces, pennyweights, or grains.
All other fields update instantly with the converted amounts.
Use the direction arrows to see which unit you are converting from.
Click "Copy" next to any result to copy the value to your clipboard.
Click "Reset" to clear all fields and start a new conversion.

Use cases

Price gold or silver bullion by converting spot prices from troy oz to grams.
Verify pennyweight measurements when appraising jewelry.
Convert grain weights for gemstone and gold grain pricing.
Check avoirdupois vs. troy ounce differences when comparing product listings.
Calculate the weight of a gold chain in grams from a troy oz specification.
Cross-reference weight units on precious metal purchase invoices.

Frequently Asked Questions

Last updated: 2026-06-19 · Reviewed by Nham Vu