Popular conversions
3 pairsFine Silver (999) ↔ Sterling Silver (925)
999 ↔ 925
Sterling Silver (925) ↔ Coin Silver (900)
925 ↔ 900
Coin Silver (900) ↔ 800 Silver
900 ↔ 800
Unit guides
4 unitsDetailed guide to Silver Purity
Silver purity is expressed as millesimal fineness: parts per thousand that are pure silver. A value of 925 means 925 out of 1000 parts are pure silver, with the remainder made up of other metals, usually copper.
Converting between fineness grades is useful when comparing jewelry, estimating pure-silver content and understanding how alloy composition affects durability and value.
- Physical quantity group
- Silver purity by millesimal fineness
- Reference purity
- 999 = fine (pure) silver basis
- Purity expression
- Parts per thousand (‰)
- Typical use
- Jewelry, silverware and alloy comparison
- Common values
- 999, 925, 900 and 800
What does silver fineness mean?
Fineness expresses how many of 1000 parts are pure silver. For example, 925 means 925 parts pure silver and 75 parts alloying metal, almost always copper.
This ratio affects hardness, tarnish resistance and how the piece is priced relative to its pure-silver content.
Comparing 999, 925, 900 and 800
999 (fine silver) is the pure-silver reference and is very soft, so it is mostly used for bullion and investment pieces rather than everyday jewelry.
925 (sterling silver) is the standard used worldwide for jewelry and silverware because the small copper addition makes it far more durable. 900 (coin silver) and 800 silver contain progressively less pure silver and were historically common in coinage and older European and Ottoman-era silverware.
Why fineness conversions matter
When a known mass is converted from one fineness grade to another, the pure-silver portion stays conceptually central while the alloy proportion changes.
These conversions are useful for pricing, comparing jewelry specifications and understanding what a stamped fineness mark means in physical silver content.
Unit comparison table
| Unit | Symbol | SI equivalent | System | Common use |
|---|---|---|---|---|
| Fine Silver (999) | 999 | 99.9% pure silver | Jewelry/bullion standard | Bullion, investment silver |
| Sterling Silver (925) | 925 | 92.5% pure silver | Jewelry standard | Jewelry, rings, silverware |
| Coin Silver (900) | 900 | 90% pure silver | Historical coinage standard | Pre-1965 coins, some traditional silverware |
| 800 Silver | 800 | 80% pure silver | European jewelry standard | Antique and traditional silver items |
Silver purity units
| Unit | Symbol | Information |
|---|---|---|
| Fine Silver (999) | 999 | View unit guide |
| Sterling Silver (925) | 925 | View unit guide |
| Coin Silver (900) | 900 | View unit guide |
| 800 Silver | 800 | View unit guide |
Sources
The definitions and conversion relationships on this page are aligned with standard metrology and SI reference material.