What is the fineness of sterling silver?

Sterling silver has a fineness of 925, meaning it is 92.5% pure silver by mass.

The remaining 7.5% is usually copper or another strengthening metal. Pure silver is relatively soft and can bend, scratch, or deform easily, so adding a small amount of another metal makes sterling silver more practical for jewelry, tableware, decorative objects, and musical instruments.

The number 925 is a millesimal fineness mark: it describes 925 parts of silver out of 1,000. In percentage terms, that is 92.5%; in older British terminology, sterling silver is also associated with the “925” standard and the traditional lion passant hallmark.

Sterling silver is often confused with fine silver, which is commonly marked 999 and contains at least 99.9% silver. Gold fineness works differently in everyday labeling: 18-karat gold, for example, is 750 fineness. Silver-plated objects are another separate category—their surface contains silver, but the item is not solid sterling silver.