A 925 stamped inside a ring or on a clasp is a statement of fineness: the silver parts of the piece are meant to be 925 parts of pure silver in every 1,000, which is 92.5%. That is the sterling standard, and it is the one silver standard that the US, the UK and India all recognise. What the number promises, who stands behind it and how strictly it is held differ by country, and this page goes through each, using the rules themselves. It puts no value on any piece.
What the number means
Fineness on precious metal is written in parts per thousand, so the arithmetic is direct: 925 ÷ 1,000 = 0.925. A piece whose silver parts weigh 20 g and that truly meets the mark contains 18.5 g of pure silver. The other 75 parts per thousand are other metals. The mark does not name them, and no rule quoted on this page requires it to.
“Sterling” is the name for the same standard. In the US the word and the number are tied together by regulation; in the UK the number is the legal mark and “sterling” is the traditional name for the 925 standard.
In the United States: a seller’s claim, held to a definition
The FTC’s Jewelry Guides, at 16 CFR § 23.5, set out what silver words may mean. Calling a product “solid silver”, “Sterling Silver”, “Sterling” or “Ster.” is misleading unless it is at least 925/1,000ths pure silver. The bare word “silver” may not be used on its own: the guide treats it as misleading unless an equally conspicuous fineness mark immediately precedes it, as in “750 silver”. That is why a number is the normal way to describe silver that is not sterling.
Two more parts of the same section matter for a 925 stamp. Describing a product as silver when it is only coated is misleading unless the description makes the coating clear. And Note 1 to the section points out that the National Stamping Act bars silver-plated articles from being marked “sterling” or “coin”. The silver plated vs sterling guide covers that line in full.
What the US does not have is an independent test before sale. Nothing requires a maker to stamp silver at all, and no government office checks it first. The stamp is the maker’s or seller’s claim, and the law fixes what the claim must mean.
How far short a US 925 may fall
The National Gold and Silver Stamping Act, at 15 U.S.C. § 296, allows a small divergence. A silver part tested without solder may fall short of 925 by no more than four parts per thousand, so 921 is the floor. The whole article, solder included and assayed as one piece, may fall short by no more than ten parts per thousand, so 915. The Act says the two tests are concurrent: both must be met. § 23.5 states that its rules are subject to these tolerances.
The silver stamp tolerance calculator works out the lowest lawful fineness for any US silver mark, the words “sterling” and “coin” included.
In the United Kingdom: tested before it is sold
Under the Hallmarking Act 1973, 925 is one of four silver standards, alongside 800, 958.4 and 999. Schedule 2 sets the standard mark for it as the figures 925, struck inside a shield whose outline shows the metal is silver. The optional pictorial mark for 925 is a lion passant, or a lion rampant when the Edinburgh Assay Office strikes it. The UK hallmark symbols tool lists every standard with its mark.
The difference from the US is who makes the statement. In the UK a silver article above the exemption weight of 7.78 g may not be described as silver in trade unless an assay office has tested it and struck a hallmark. A 925 inside a UK hallmark is therefore the assay office’s finding, not the maker’s claim. A plain “925” stamp with no sponsor’s mark and no assay office mark beside it is not a UK hallmark. The guide to UK hallmarking sets out the compulsory marks, and the exemption weights tool checks the weight rule.
In India: a BIS grade
India’s silver hallmarking standard, IS 2112, lists 925 as a grade in both its 2014 and its 2025 editions. Silver hallmarking in India is voluntary, but a piece hallmarked under the current scheme carries the BIS mark with the word SILVER, the grade and a HUID code. The India silver hallmark grades page has both lists and the sources for them.
What a 925 stamp does not tell you
- Who made it. A bare number identifies no maker. A UK hallmark includes a sponsor’s mark; a US stamp may or may not sit beside a maker’s mark.
- That the whole piece is silver. Stones, cores, springs and fittings are not part of the fineness claim, and a stamp on one part speaks for that part.
- That it is genuine. A stamp is a mark on metal, and a mark can be struck on anything. The fake hallmark guide covers the signs that one does not fit the piece it is on.
- What it is worth. The silver content gives a melt value, which the silver value calculator works out at the live price. What a piece fetches as an object is a different number, and this site keeps the two apart.
925 beside other silver marks
Under § 23.5, “coin” or “coin silver” requires at least 900/1,000ths, so coin silver is below sterling. The UK’s Britannia standard, 958.4, is above it; the Britannia silver guide explains that mark. The silver purity by country table sets the US, UK and Indian standards side by side.
Sources
- 16 CFR § 23.5, FTC Guides for the Jewelry, Precious Metals, and Pewter Industries (Cornell LII), including Note 1.
- 15 U.S.C. § 296, National Gold and Silver Stamping Act (govinfo.gov).
- Hallmarking Act 1973, Schedules 1 and 2 (legislation.gov.uk).
- Press Information Bureau, Ministry of Consumer Affairs, release 2163768 (4 September 2025), on IS 2112:2025.