Where the numbers come from
Two kinds of number appear on this site. Both are stated exactly, and neither is estimated.
Specifications
Weight, fineness and diameter are set by statute - the Coinage Acts - and published by the United States Mint. They are facts about what a coin is, not opinions about what it is worth, and they do not change.
Silver weight is calculated, not transcribed. Every actual silver weight on the site is derived at render time as grams multiplied by fineness, divided by 31.1034768, the grams in a troy ounce. A transcribed constant is a constant that can be wrong; a derived one cannot drift from its inputs.
Melt value
Melt value is the silver weight multiplied by the live silver spot price. The price comes from a market feed, is cached for fifteen minutes, and is checked against sanity bounds before it is used - if a feed changes format and starts returning something that is not a plausible dollar price, the site renders nothing rather than rendering nonsense.
Where no live price can be reached, pages say so and show the silver weight alone. There is no fallback to a stale hardcoded price anywhere on the site.
What we deliberately do not publish
- Catalogue values. What a coin is worth in a given grade comes from proprietary datasets. We do not licence them, and generating plausible-looking numbers instead would make everything else here untrustworthy.
- Mintage figures. These are public record but are not available from any source we can fetch and verify programmatically. Publishing a few hundred numbers we could not check would be exactly the kind of confident-sounding error the readers of a reference site notice first. Where a production fact matters - a year nothing was struck, an issue that never left mint sets - it is stated in prose on the relevant page instead.
- Grades and appraisals. Both require the coin in hand.
Why the date pages start at 1892
1892 is the first year of the Barber half dollar and the point at which the modern 30.6mm, 12.50 gram specification settles. Everything from there to today is a coin somebody might reasonably find in a drawer, and melt value is a useful way to think about it.
Earlier half dollars are covered by series rather than by date. They are collected as rarities, their value has almost nothing to do with their silver, and a melt figure would be actively misleading on a coin worth several hundred dollars or more.
Corrections
If something here is wrong, we want to know and we will fix it and say that we did. The address is hello@halfdollars.com.