Weight units
Markets use the (≈31.1035 g). One kilogram is about 32.15 troy ounces. Large institutional bars ('London Good Delivery') weigh roughly 400 troy ounces — about 12.4 kg.
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
Purity
Purity is expressed as karats (24k = pure) or in parts per thousand (999.9 = 99.99% pure). Jewellery is often 14k or 18k, meaning it contains other metals.
Market prices refer to pure gold. A piece of jewellery contains less gold than its total weight suggests.
Key takeaways
- 1 troy oz ≈ 31.1 g; 1 kg ≈ 32.15 troy oz.
- 24k or 999.9 fineness means essentially pure gold.
- Quoted prices refer to pure gold.
Knowledge check
How much pure gold is in a 10 g ring made of 18k gold?
Key terms · hover or tap for a definition