Data Sources & Methodology

Specimen data

The physical backbone of this site is the collection database of the American Numismatic Society (ANS), one of the world's foremost numismatic research institutions. Measured weights, diameters, die axes, legends and mint attributions for real coins are derived from the ANS collection, which is published as open data under the Open Database License (ODbL). We aggregate individual specimens into coin-type references rather than republishing the source database. Full attribution is on our licensing page.

Coin photographs appear only for issues struck in 1925 or earlier, which the ANS marks as public domain. Later issues display an illustrative rendering until independently licensed photography is added.

Mintages

Mintage figures come from published United States Mint annual reports as compiled in standard references. They are labeled approximate: historical Mint accounting often mixed fiscal and calendar years, and some branch-mint figures remain debated among researchers.

Melt values

Melt values are computed, not estimated: official metal content of each coin type multiplied by the spot price of silver, gold or copper. Spot prices are refreshed from market data and every melt figure on the site carries its as-of date. When prices cannot be refreshed, the last stored values are used and dated accordingly.

Collector value estimates

Grade-by-grade collector values are modeled estimates unless marked verified. The model combines three inputs: mintage rarity tier, a hardcoded list of recognized key dates, and intrinsic metal content as a floor. Rows marked verified have been checked against current dealer retail listings by hand.

We do not fabricate auction records, and we label every number with its source and date. Treat estimates as orientation, not appraisal: certification, eye appeal, toning and market timing all move real prices. For coins that may be worth four figures or more, a professional grading service (PCGS or NGC) is the right next step.

Corrections

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