1 Troy Ounce of Gold in Grams: Purity & Bullion Math
1 Troy Ounce of pure .9999 gold weighs exactly 31.1035 grams (not 28.35g). Calculate spot value, karat purities, and bullion coins.
Primary answer1 Troy Ounce = 31.1035 Grams
Secondary1.097 Avoirdupois Ounces • 20 Pennyweights (dwt) • 480 Grains
Metric31.1035 Grams (Pure Gold .9999)
Mass = 1 ozt × 31.1034768 g/ozt = 31.1035 grams pure .9999 gold
Quick conversion matrix
| Measurement | Equivalent A | Equivalent B | Equivalent C |
|---|---|---|---|
| 1 Troy Ounce (24K Pure Gold) | 31.1035 Grams | 1.00 ozt Pure Au | .9999 Fine Bullion |
| 1 Avoirdupois Ounce (Kitchen/Postal) | 28.3495 Grams | 0.911 ozt | Scrap buyer trap |
| American Gold Eagle 1 oz (22K) | 33.9300 Grams (Gross) | 31.1035g Pure Au | Alloyed with Ag & Cu |
Chef & measurement rules
01
Never weigh precious metals in kitchen avoirdupois ounces; always verify your digital scale is set to "ozt" (31.10g) not "oz" (28.35g).
Why 1 Troy Ounce is 31.1035 Grams
1 Troy Ounce (ozt) is defined as exactly 31.1034768 grams (480 troy grains).
This is 2.75 grams (9.71%) heavier than a standard avoirdupois kitchen ounce (28.35g). All global spot market quotes (COMEX, LBMA) are quoted per Troy ounce.
Frequently Asked Questions
Why is a Troy ounce heavier than a regular ounce?
The Troy system (dating to Troyes, France) defines 1 ozt as 480 grains (31.1035g), whereas an avoirdupois ounce is 437.5 grains (28.3495g).