A metal ratio tells you how many ounces of one metal one ounce of another buys. Traders watch ratios to spot cheap/expensive metals relative to each other — a high gold:silver ratio, for example, has historically signalled silver is undervalued. Tap a card below to see its history.
UK precious metal purity reference
The numbers shown on hallmarks (.925, .750, etc.) are the millesimal fineness — parts per thousand of the pure metal. UK gold is also commonly described in carats, where 24ct represents pure gold.
| Metal | Purity | Decimal | Common name |
|---|---|---|---|
| 24ct | .999+ | Fine / pure gold | |
| 22ct | .916 | 22 carat (sovereign / Krugerrand) | |
| 21ct | .875 | 21 carat | |
| 18ct | .750 | 18 carat (premium jewellery) | |
| 14ct | .585 | 14 carat | |
| 9ct | .375 | 9 carat (UK high-street) | |
| Fine | .999 | Investment-grade fine silver | |
| Britannia | .958 | British Britannia coins / hallmark | |
| Sterling | .925 | Sterling silver | |
| Coin | .500 | Pre-1947 UK coin silver | |
| Fine | .9999 | Investment-grade platinum | |
| Fine | .9999 | Investment-grade palladium |
Bullion-grade fine metals (.999 silver, .999 gold, .9999 platinum, .9999 palladium) are valued at 100% of spot in this calculator — see the FAQ for why.
Frequently asked questions
What is the spot price of gold today?
The spot price is the live market rate for one troy ounce of pure (.999+) gold. The Calculator and Charts tabs show the latest rate in your chosen currency, refreshed every 60 seconds.
What does .925 mean on silver?
It means the metal is 92.5% pure silver. This is the standard for sterling silver and the most common purity for UK jewellery and tableware.
Why is the .999 row valued at 100% of spot, not 99.9%?
It's a bullion convention. Fine .999+ metal is treated as effectively pure for valuation — dealers don't recover the trace 0.1% of impurities, so they buy and sell .999 silver, .999 gold, .9999 platinum and .9999 palladium at full spot.
What is the gold to silver ratio?
The number of ounces of silver one ounce of gold buys. Historically it's swung between roughly 15:1 and over 100:1. The Ratios tab tracks it live and over time, plus other useful pairs like Platinum:Gold.
Can I see charts for a specific purity, like 18ct gold or sterling silver?
Yes — and this is the main reason to use this site. Every metal in the Charts tab has a purity dropdown next to it. Switch gold to .750 (18ct), or silver to .925 (sterling), and the entire chart, tooltip and statistics show that exact purity over time, not pure spot. Same for 9ct gold (.375), 22ct gold (.916), Britannia silver (.958), 14ct gold and so on. The History tab also has a per-metal purity selector for any past date. This is the difference between everyone else's "spot price chart" and what you actually need to know — what your specific item is worth.
Can I change the currency to USD, EUR or another currency?
Yes — use the currency selector at the top of the page. It applies to every tool: Calculator, Charts, Ratios, History and Convert.
How much is 9ct gold per gram?
9 carat gold is 37.5% pure (.375). Multiply the spot price per gram of pure gold by 0.375 — or read the .375 row in the Calculator tab.
What is OHLC?
Open / High / Low / Close — the four reference prices for a trading day. The History tab shows OHLC for any past date you pick.
How do I calculate the scrap value of gold or silver?
Multiply the weight by the spot price, then by the purity (e.g. 0.750 for 18ct), then by the percentage of spot a buyer is offering. Use the Spot % field on the Calculator tab — set it to 90 to see what 90% of spot looks like.
Is this calculator accurate?
Spot prices come from a live market data feed and refresh every minute. Calculations use exact unit conversions (1 troy ounce = 31.1034768 grams) and are accurate to two decimal places. This tool is for guidance only and is not a financial offer.