Metal price and calculator methodology

1. Scope and purpose

Our calculators are educational tools for converting a user-supplied market reference into an estimated contained-metal value. They are designed to make units, purity and modeled payout visible. They do not identify, authenticate, assay or appraise an object, and they do not predict a buyer's offer.

Guides explain market conventions in plain language. Long-form research pages are separately sourced historical works. We distinguish calculations, reported facts, interpretations and examples wherever that distinction affects the reader's decision.

2. Reference-price policy

The visitor supplies the reference price. Gold, silver, platinum and palladium calculators are based on a price per troy ounce. The copper calculator is based on a price per avoirdupois pound. Each calculator labels that basis next to the input.

The site does not check whether a manually entered number is current, whether it is a bid, ask or midpoint, or whether its currency matches a particular transaction. The currency symbol is a display convention; calculations are currency-neutral as long as inputs use one consistent currency.

Before using a reference, record:

• metal and grade or purity represented;
• currency and unit;
• whether the quote is bid, ask, midpoint, benchmark or contract;
• source and timestamp;
• any delay or market-status label.

3. Weight constants

Browser calculations convert all supported inputs to grams. The constants are:

The weight converter uses the same constants. Interface results are rounded for readability; internal calculation uses JavaScript floating-point arithmetic and the constants above.

4. Purity and fineness

Purity is entered as a percentage. A value of 99.9 means 99.9%, or a decimal fineness of 0.999. Preset names on a calculator are conveniences, not test results. Hallmarks may be absent, forged, worn or inapplicable to every component of an item.

For gold karat, the theoretical relationship is karat divided by 24. Thus, 18 karat corresponds to 75% gold in the simple model. Legal tolerances, solder and item construction can complicate real objects. For silver, sterling is modeled at 92.5% only when that preset is selected.

5. Contained-metal value

First, the reference price is converted into a price per gram using the calculator's stated price basis. Then it is multiplied by fine-metal weight.

“Melt value” is used as a familiar shorthand on some tools. It means theoretical contained-metal value under the selected inputs. It does not state that an item should be melted or that a refinery will recover every theoretical gram.

6. Modeled payout

The optional payout field lets a visitor model a percentage of contained-metal value. It is not a claim about a typical, fair or available offer.

Real bids can reflect assay uncertainty, recovery loss, stones and non-metal components, minimum charges, refining, logistics, hedging, settlement time, taxes and margin. A collectible or artistic item may instead be worth more than contained metal.

7. Rounding and validation

• Negative weight or price values are rejected.
• Purity and payout must be between 0% and 100%.
• Money normally displays two decimals, with extra precision for values below one unit of currency.
• Weight outputs may display up to eight decimal places in the converter and fewer in value summaries.
• Displayed components can differ slightly from a recomputation made only with rounded display values.

8. Calculator privacy and dependencies

Calculations run locally in the visitor's browser. Calculator inputs are not submitted to All Metal Prices, saved to a database or sent to a pricing service. The current site has no third-party market-data API dependency. JavaScript is required for interactive results; the formulas and constants remain readable without it.

9. Editorial and research method

Practical guides prioritize definitions, units, formulas, limitations and decision-relevant examples. Historical research prioritizes primary sources and authoritative scholarship where available, identifies sources in notes or bibliographies, and separates evidence from inference. Downloadable documents are provided for reader convenience; the canonical web page is the version intended for ongoing correction.

For the complete content standard, see our editorial policy.

10. What our results do not include

• live or guaranteed market prices;
• currency conversion;
• tax, shipping or payment charges;
• assay or authenticity verification;
• gemstone, numismatic, antique, brand or artistic value;
• local legal restrictions or reporting obligations;
• a recommendation to buy, sell, hold or melt anything.

11. Corrections and revisions

We invite specific correction reports with the page address, disputed statement, supporting source and suggested change. Material corrections are disclosed on the affected page when practical. See Corrections for the process.

Methodology change log