The short answer
Sterling silver denotes 92.5% silver. A theoretical silver-content calculation still needs eligible metal weight and a dated reference price. It is not a guaranteed offer.
Read 925 as composition
The FTC describes sterling silver as containing 92.5% pure silver and explains the 925 mark as 925 parts per thousand. It separately describes silver plate as a layer of silver applied to a base metal. Those are not interchangeable categories.[2]
This guide estimates silver content, not collectible worth. A usable or historically interesting object may be evaluated on different terms by different buyers. Do not destroy an object merely because a metal calculation is easy to perform.
Gross weight is not always silver-alloy weight
The useful input is the mass of the eligible sterling alloy. An item with non-silver components cannot automatically be treated as a solid lump of sterling. If you do not know what portion of the weight belongs to the alloy, report a range based on explicit assumptions or leave the estimate unresolved.
For silver-plated material, a 92.5% multiplier applied to total weight is the wrong model. The FTC’s distinction between sterling and plating explains why material identification must come before arithmetic.[2]
Calculate with compatible units
Hypothetical example: 40 grams of eligible sterling alloy × 0.925 = 37 grams of fine silver. At a hypothetical reference price of 2 currency units per gram, the theoretical silver-content value is 74 currency units. These are teaching inputs, not today’s silver price.
If your reference is quoted per troy ounce, first convert it using a verified unit definition or obtain a per-gram reference from the same source. Keep the unit and currency beside every intermediate value. Do not paste a price labeled only “oz” into a gram-based calculation without resolving the unit.
Turn an offer into a comparable number
Suppose a buyer offers 60 currency units against that hypothetical 74-unit metal estimate. The offer-to-estimate ratio is 60 ÷ 74, approximately 81.1%. This is a descriptive ratio, not evidence that the offer is fair or unfair. Fees, eligibility, testing and the reference timestamp still need checking.
Ask whether the quoted amount is before or after deductions, whether shipping or return charges apply, and whether the weight and purity are provisional. Compare net amounts for the same lot rather than a headline percentage from one seller and a final payout from another.
Avoid false floors
Theoretical metal value is not a guaranteed minimum payout. This page has no verified buyer quotations and does not publish a universal refiner discount. An apparently precise percentage range would overstate the evidence available.
Keep photographs of marks, a weight record, your reference source and time, and the written offer together. The FTC source establishes U.S. labeling concepts; it does not authenticate your object. If material identification remains uncertain, the defensible next step is independent assessment, not a larger spreadsheet.[2]
Sources & scope
Links support definitions and methodology. Worked examples are hypothetical, not quotes; the review date is not the observation date of a market value.