18ct Gold Price per Gram — UK Live Calculator
18-carat gold is 75% pure — the high-end standard for engagement rings, designer jewellery and serious wedding bands. This is the live UK price per gram of 18ct gold, the formula behind it, and a calculator to do the maths on any weight.
Live 18ct gold (.750) calculator
Live gold spot: loading… per troy ounce. 18ct price per gram: —.
More options (mixed lots, multiple items, charts): full Spot Bot calculator.
What is 18ct gold?
18ct gold is an alloy that is 75% pure gold, with the remaining 25% made up of silver, copper, palladium or nickel depending on whether the piece is yellow gold, white gold or rose gold. It's the international sweet spot for fine jewellery — pure enough to glow with a real gold colour, but durable enough for daily wear.
In the UK, 18ct is the standard for engagement rings, premium wedding bands and serious designer pieces from houses like Cartier, Boodles, and Tiffany. The hallmark is "750".
The formula for 18ct gold value
The maths for 18ct value per gram:
18ct value/g = (spot_per_oz ÷ 31.1034768) × 0.750
If spot is £2,100/oz:
- Fine gold per gram: £2,100 ÷ 31.1035 = £67.52/g
- 18ct per gram: £67.52 × 0.750 = £50.64/g
- Value of a 5g 18ct ring: 5 × £50.64 = £253.20
Note: 5g of 18ct gold has exactly the same melt value as 10g of 9ct gold — both contain 3.75g of pure gold.
What 18ct typically fetches as scrap
Because 18ct is twice as gold-dense as 9ct, dealers tend to pay a slightly higher percentage of spot for it — less work to refine, fewer alloy metals to skim off:
- Refiners: 92–97% of melt value
- Specialist scrap-gold-by-post: 90–95%
- Jewellers, pawnbrokers: 75–88%
- High-street cash-for-gold: 60–80%
Always weigh stones separately — if you're scrapping an engagement ring, the dealer will pay only for the gold weight, not the diamond or sapphire.
18ct white gold vs yellow gold vs rose gold
All three contain the same 75% gold. The colour comes from the alloy mix:
- Yellow: 75% gold, ~15% silver, ~10% copper
- White: 75% gold, the rest is palladium, silver and trace nickel (some white golds are rhodium-plated on top — the plating wears off with time)
- Rose: 75% gold, ~22% copper, ~3% silver
From a scrap perspective they're all valued the same — only the gold content matters.
Tracking 18ct holdings
If you've inherited or are collecting 18ct gold pieces, you can save each item to your Spot Bot portfolio with photo, weight, purity and purchase date, then watch their value change live. Free tier covers up to 15 items; Pro removes the cap and adds price alerts.