Where the numbers come from

Gold spot reference

The current primary adapter requests XAU from MetalpriceAPI using a server-side API key header. Its USD/XAU response is inverted into USD per troy ounce, then checked for a valid timestamp, plausible price, and monotonic provider time. If the primary request fails, the server may use Gold API as a secondary fallback; the displayed source remains explicit.

Foreign-exchange reference

Frankfurter supplies the USD-to-EUR, GBP, CAD, and AUD reference rates used for optional display currencies. These are reference rates and may update on a different schedule from a live trading quote, so the interface shows the provider date when available.

How the estimate is calculated

One troy ounce is treated as 31.1034768 grams. The per-gram spot value is the troy-ounce value divided by that constant; a purity factor is then applied for the selected karat. Currency conversion uses the selected reference rate.

The result is a theoretical spot / melt value estimate. It excludes dealer spreads, product premiums, taxes, assay fees, refining costs, labour, and condition.

Freshness and provider limits

Provider responses are fetched on the server and cached for the configured refresh window. When a request fails, the last valid value may be marked stale; when no valid value exists, the page reports that the data is unavailable instead of inventing a price.

Provider availability, terms, commercial display permissions, cache permissions, redistribution rules, and request limits remain separate questions. Anyone planning commercial reuse should review the providers' current documentation and terms directly.