Gold and silver hallmarks explained
How to read a UK hallmark, what each fineness number means, and which items don't need one.
What's in a UK hallmark
Assay Office London lists three compulsory marks:
- Sponsor's mark: the initials of the maker or the company that sent the item for testing.
- Fineness mark: a number showing the precious metal content in parts per thousand, such as 375 or 925.
- Assay office mark: which office tested it (London, Birmingham, Sheffield or Edinburgh).
A traditional fineness symbol and a date letter are optional extras.
Gold fineness and carats
| Mark | Carat | Pure gold | Today's price |
|---|---|---|---|
| 375 | 9ct | 37.5% | 9ct price |
| 585 | 14ct | 58.5% | 14ct price |
| 750 | 18ct | 75% | 18ct price |
| 916 | 22ct | 91.6% | 22ct price |
| 999 | 24ct | 99.9% | 24ct price |
All UK standards and weight exemptions
| Metal | Approved standards | No hallmark needed under |
|---|---|---|
| Gold | 999, 990, 916.6, 750, 585, 375 | 1.0 g |
| Silver | 999, 958, 925, 800 | 7.78 g |
| Platinum | 999, 950, 900, 850 | 0.5 g |
| Palladium | 999, 950, 500 | 1.0 g |
For items that mix precious and other metals, the exemption is based on the total metal weight. Source: UK Assay Offices' Hallmarking Guidance Notes.
Common questions
What does 375 on gold mean?
It is the fineness mark for 9 carat gold: 375 parts in every 1,000 are pure gold.
What does 925 mean on silver?
It is the sterling silver standard: 925 parts in every 1,000 are pure silver.
Why doesn't my ring have a hallmark?
Gold items under 1 g and silver items under 7.78 g don't have to be hallmarked in the UK. Older or foreign items may also be unmarked.
Sources
- UK Assay Offices: Hallmarking Guidance Notes (November 2022)
- Assay Office London: What is a hallmark?
Last reviewed October 2026. Spotted a mistake? Email hello@goldpergram.co.uk. How we calculate