What 18ct gold is worth: how the per-gram figure is worked out

What 18ct gold means in practice

18ct gold is 75% pure gold by weight, alloyed with silver, copper and sometimes palladium. The British hallmark is usually 750. Because it carries twice the gold content of 9ct, an 18ct piece will always pay more per gram than its 9ct equivalent of the same weight. If you already know what you have and want the process rather than the arithmetic, the service page to sell 18ct gold sets out the label, the timings and the paperwork.

Most fine jewellery from European, Italian and Middle Eastern makers is 18ct. Designer brands such as Cartier, Bulgari, Tiffany and many independent goldsmiths use 18ct as standard. Wedding bands from the 1900s through to the 1960s in the UK are often 18ct or 22ct rather than 9ct.

How an 18ct postal offer is built

The starting point is the live precious-metal market on the day your parcel is tested. We confirm the purity (around 0.75 for 18ct) and weigh the gold, and the offer reflects that weight and purity against the market, with our refining cost and margin already accounted for, so nothing further is taken off. Stones, springs, clasps in another metal and non-gold solder are weighed out so you are not charged for them and not paid for them either. Each line of that working is explained in GoldPaid’s valuation method.

If you are holding a branded designer piece, mention it on WhatsApp before posting. Some 18ct items are worth more intact than melted, and we will tell you how we would value yours before you post anything.

What we look for on 18ct

On 18ct work the hallmark should read 750, or an older mark such as 18, 18ct, or the crown used alongside the carat figure on older gold. Colour tells you very little: rose, white and yellow 18ct carry slightly different alloys but the same gold content. Construction matters more. Hollow 18ct rope chains and electroformed pieces feel lighter than they look, and we would rather you knew that before the parcel goes in the post.

White 18ct often has a rhodium plating that wears through to a warmer tone underneath. That is normal and does not change the gold content.

Posting an 18ct parcel safely

1. WhatsApp 07944 014111 with daylight photos and a short note describing each piece.
2. We confirm the right label for the value and email a prepaid Royal Mail Special Delivery label.
3. Wrap each piece in tissue or a small zip-bag, pad the box, seal it.
4. Drop the parcel over the counter at any Post Office and keep the receipt.
5. We text you on arrival, then send a written offer once each item has been XRF-tested.
6. Accept by reply and we aim to pay by Faster Payments within one working hour of your acceptance. Decline for free tracked return.

When 18ct is not actually 18ct

Two things catch sellers out. Early twentieth-century "gold-filled" and "rolled gold" jewellery puts a thick layer of 18ct sheet over a base-metal core, and a surface acid test can read it as solid 18ct because the surface is 18ct. Wear points, cut ends and the weight give it away. The other is foreign jewellery stamped 750 that comes back at 14ct or lower once tested through, older holiday-souvenir pieces especially.

We test each piece, not the parcel as a whole, so if one ring is solid 18ct and one is plated, your written offer separates them rather than averaging.

Designer 18ct: when to sell intact

Branded 18ct from a recognisable maker (Cartier Love bracelets, Bulgari Tubogas, Tiffany T) can pay more on the secondary collectors market than as scrap metal. If yours has a serial number or box and papers, send a photo on WhatsApp first and we will tell you how we would value it before you post anything. Nothing is melted before you accept a written offer on the postal buying service.

For broken designer pieces with no resale path, the metal offer is usually the right answer. You can also compare with our guide to selling broken gold jewellery by post.