Published 2 June 2026
Why no honest buyer fixes a single £-per-gram figure
Gold is a globally traded commodity. The London Bullion Market Association (LBMA) fixes a reference price twice a day, and the live spot market moves continuously in between. A buyer who quotes the same £-per-gram figure on Monday morning and Friday afternoon is either ignoring the market or hedging against having to honour their own promise.
The honest position is: the offer is set against the live market at the moment of valuation. The maths below shows you exactly how that works.
Step 1: the LBMA spot price
The LBMA fixes the gold price in US dollars per troy ounce twice a day, at 10:30 and 15:00 London time. The fix is published live on the LBMA website. UK buyers convert this to GBP using the live exchange rate, or use the live spot price quoted directly in GBP by a market data feed.
For the rest of the calculation, the input is "live GBP per troy ounce of pure gold". For our live tracker page see live gold price.
Step 2: convert ounce to gram
This is the price per gram of 999 fine gold at the wholesale market. It is not the scrap offer. It is the input the rest of the calculation builds on.
Step 3: apply the karat decimal
Multiply the price per gram of pure gold by the karat decimal of the alloy you are valuing. 9ct (0.375), 14ct (0.585), 18ct (0.750), 22ct (0.916), 24ct (0.999).
A 1 gram 18ct ring contains 0.75 grams of pure gold. A 1 gram 9ct ring contains 0.375 grams. The recovered gold value scales linearly with the karat decimal.
Step 4: refining margin and dealer margin
The figure from step 3 is the raw value of the gold content. The buyer subtracts a refining margin (typically 3 to 7% depending on the karat and the form factor) and a dealer margin (the buyer's operating cost and profit) to arrive at the offered price per gram.
9ct, with more base metal in the alloy, generally carries a slightly wider refining margin than 18ct or 22ct because the refining chemistry has to do more work per gram of recovered gold. Bullion-grade 999 carries the smallest margin because no refining is needed.
Worked steps you can do yourself
- Find the live LBMA gold price in GBP per troy ounce (kitco.com, lbma.org.uk, or our live page).
- Divide by 31.1035 to get GBP per gram of pure gold.
- Multiply by the karat decimal (0.375 for 9ct, 0.585 for 14ct, 0.750 for 18ct, 0.916 for 22ct, 0.999 for 24ct) to get the GBP per gram of raw alloy.
- Subtract a typical refining margin of 5% as a working estimate to get a buyer's indicative scrap price per gram.
- Multiply by the weight of your piece in grams to get an indicative recovered value.
Why your final offer can differ from the back-of-envelope figure
A back-of-envelope calculation gives you a sensible indicative figure but it does not account for the inspection. Stones add weight to the piece that is not gold. Solder joints, clasps, watch parts, magnets, springs and other non-gold components are excluded. Hallmarks may not match the actual alloy. The XRF test confirms the real metal content, and the offer is built on the test, not on the stamped mark.
Final offers depend on inspection, item weight, purity, hallmarks, stones, non-gold components, condition and the live precious-metal market.
Why we do not publish a fixed £-per-gram on this guide
Anyone publishing a fixed £-per-gram on a guide is either dating that guide minute by minute or quietly out of date. The maths is the durable answer: it works the same way every day, at any market level. The live figure changes constantly. We publish the live tracker on the gold price page so you can apply the maths to today's number.
A practical close
Gold pricing is not a black box. The inputs are public, the maths is one division and two multiplications, and the margins are honest figures a buyer can explain. If you do the back-of-envelope sum and post a parcel, you will arrive at a written valuation that lines up with what you calculated, plus or minus the inspection details. That is what an honest buyer commits to, and that is the test for any UK gold buyer worth posting to.
Common questions
How many grams in a troy ounce?
31.1034768 grams, almost always rounded to 31.1035 in market calculations.
Why does the price change every day?
Gold trades on global markets continuously. The LBMA reference price is fixed twice daily but the live spot moves second by second.
Why is 18ct paid more per gram than 9ct?
The karat decimal is twice as high. There is twice as much gold in each gram of 18ct as in each gram of 9ct.
What is a typical refining margin?
For mixed scrap jewellery, typically 3 to 7% depending on the karat, the form factor and the volume of the parcel. Bullion-grade 999 carries the smallest margin.
Can I check the maths after I get a valuation?
Yes, and you should. Take the live spot, do the four steps, compare to the offer. The written valuation should align with the working margin.
Does GoldPaid publish a daily price list?
The live spot price is shown on the gold price page. The offered scrap price per gram by karat is calculated at the moment of valuation, not posted in advance.
Why do some buyers advertise a flat price?
Marketing. A flat advertised figure usually sits well below the live market so the buyer is protected against price moves. The actual offer at the counter can be higher or lower depending on the day.
How accurate is a kitchen scale for the weight?
A kitchen scale gives a rough check. Buyers weigh on calibrated jewellery scales to the hundredth of a gram. The written valuation uses the calibrated weight.