Two different ounces
The everyday (avoirdupois) ounce is about 28.35 g. The is about 31.10 g — roughly 10% heavier. Precious metals are always quoted in troy ounces.
The name traces back to Troyes, a French market town where the unit was standardised in medieval trade fairs.
Gold weights at a glance
1 troy oz
31.10 g
1 regular oz
28.35 g
1 kilogram
32.15 troy oz
Good Delivery bar
≈400 troy oz
Key takeaways
- Troy ounce ≈ 31.10 g; regular ounce ≈ 28.35 g.
- All gold prices are per troy ounce.
Knowledge check
A troy ounce compared with a regular ounce is…
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