Price and calculator methodology

From a metal quote to euros per gram

The calculation is: USD per troy ounce × EUR per USD ÷ 31.1034768. Prices come from gold-api.com and conversion rates from Frankfurter. The provider response is cached briefly at the origin; price-bearing HTML can be cached for 15 minutes. The displayed timestamp records quote retrieval, not a guaranteed exchange execution time.

Unavailable or delayed data

If a provider fails, an available real cached result may be retained with its original timestamp and a stale-data notice. If there is no valid quote, values are shown as unavailable. Missing high, low or change statistics are not inferred from made-up prices.

Purity and fine weight

Fine weight equals gross gold-bearing weight × fineness as a decimal. Examples: 18K/750 uses 0.750, 585 uses 0.585, and 875 uses 0.875. The pure-gold reference uses 1.0. A specific 999 or 999.9 product must be evaluated at its stated fineness. Stones and non-gold parts require separate treatment.

Buyback estimates

Estimated payout equals calculated metal value × an assumed payout percentage. Values such as 95% are example assumptions, not surveyed market averages or verified dealer offers. Testing, payable weight, fees and the buyer's conditions determine the actual amount. See the worked price-comparison guide.

Historical charts

The gold series uses monthly USD observations from DataHub. It is not a tick, daily-close or intraday series. Euro values use the conversion rate supplied when the chart is rendered; they are not a historical EUR-price series. Comparisons select actual calendar months and omit unavailable observations.

Tax illustrations

The calculator simplifies holding-period and annual-gain questions. The €1,000 rule is a threshold for total relevant annual private-disposal gains, not an allowance automatically available for every gold sale. It does not calculate an individual's tax liability or establish investment-gold status. Refer to § 23 EStG and § 25c UStG.