Coin Specification Reference
Diameter, alloy composition, expected metal-weight breakdown, matching holder size, and storage humidity band for common US coin types and eras — a composition and dimension reference, not a valuation of any kind.
Denomination, diameter, composition, and derived figures
| Denomination | Era | Diameter | Composition | Total weight | Metal breakdown | Holder size |
|---|---|---|---|---|---|---|
| Cent | 1982–present | 19.05mm | Zinc 97.5% / Copper 2.5% | 2.5g | Zinc: 2.438g / Copper: 0.063g | 19mm capsule/flip |
| Cent | pre-1982 | 19.05mm | Copper 95% / Zinc & Tin 5% | 3.11g | Copper: 2.955g / Zinc & Tin: 0.156g | 19mm capsule/flip |
| Nickel | 1866–present (standard alloy) | 21.21mm | Copper 75% / Nickel 25% | 5g | Copper: 3.75g / Nickel: 1.25g | 21mm capsule/flip |
| Dime | pre-1965 (90% silver) | 17.91mm | Silver 90% / Copper 10% | 2.5g | Silver: 2.25g / Copper: 0.25g | 18mm capsule/flip |
| Dime | 1965–present (clad) | 17.91mm | Copper 91.67% / Nickel 8.33% | 2.268g | Copper: 2.079g / Nickel: 0.189g | 18mm capsule/flip |
| Quarter | pre-1965 (90% silver) | 24.26mm | Silver 90% / Copper 10% | 6.25g | Silver: 5.625g / Copper: 0.625g | 24.5mm capsule/flip |
| Quarter | 1965–present (clad) | 24.26mm | Copper 91.67% / Nickel 8.33% | 5.67g | Copper: 5.198g / Nickel: 0.472g | 24.5mm capsule/flip |
| Half Dollar | pre-1965 (90% silver) | 30.61mm | Silver 90% / Copper 10% | 12.5g | Silver: 11.25g / Copper: 1.25g | 30.5mm capsule/flip |
| Half Dollar | 1965–1970 (40% silver, net) | 30.61mm | Silver 40% / Copper 60% | 11.5g | Silver: 4.6g / Copper: 6.9g | 30.5mm capsule/flip |
| Half Dollar | 1971–present (clad) | 30.61mm | Copper 91.67% / Nickel 8.33% | 11.34g | Copper: 10.395g / Nickel: 0.945g | 30.5mm capsule/flip |
Metal breakdowns are computed by this site’s own Coin Metal Weight Calculator, and holder sizes by the Coin Holder & Album Size Finder— this table runs the same functions, it doesn’t duplicate their logic.
Storage humidity band
Every coin type above shares the same “Ideal” relative humidity target — 30–50% RH — because the Coin Storage & Humidity Guide classifies risk from humidity alone, not by metal. What does vary by composition is which failure mode that humidity accelerates:
- Silver-bearing rows (marked below) tarnish primarily from trace airborne sulfur, darkening gradually as humidity and time increase.
- Copper-alloy and clad rowsare the more humidity-sensitive of the two — elevated humidity accelerates spotting and, in poorly controlled storage, verdigris.
Silver-bearing types in the table above: Dime (pre-1965 (90% silver)), Quarter (pre-1965 (90% silver)), Half Dollar (pre-1965 (90% silver)), Half Dollar (1965–1970 (40% silver, net)).
What this reference is for
This table exists to answer a genuinely practical question — what should this coin weigh, what holder fits it, and how should it be stored — using nothing but publicly documented specifications and this site’s own calculators. It deliberately stops there. A coin’s grade and its scarcity are separate questions with their own dedicated references (the grade guide and the rarity scale lookup), and none of the three — specification, grade, or scarcity — is a price. This site doesn’t publish one.
Frequently Asked Questions
Is this a price guide?
No. This table covers physical specification only — diameter, alloy composition, weight, holder size, and storage humidity band. This site does not publish valuations, price guides, or investment advice of any kind.
Where do these specifications come from?
Diameter, target weight, and alloy composition are the standard, publicly documented specifications mints publish for each coin type and era — the same figures cited across numismatic references generally. Every other column (the metal breakdown, the matching holder size, the humidity band) is computed from those inputs by the same functions this site's calculators use, not entered separately by hand.
Can I use this to check whether my coin is genuine?
It's a legitimate starting point — compare your coin's measured weight and diameter against the row for its type and era, as covered in more depth in this site's guide to weight as a first authenticity screen. It is not an authentication service, and a match doesn't certify a coin any more than a mismatch condemns one; treat any meaningful discrepancy as a reason to ask an experienced collector or dealer, not a verdict.
Why do some rows share the same diameter but list different weights?
A denomination's diameter has generally stayed fixed for a given series even when its alloy changed — US silver coinage switched to a copper-nickel clad composition in the mid-1960s at the same diameters as before. Since weight depends on both volume and the density of whichever metals make up the alloy, a composition change shifts the weight even though the diameter, and therefore the matching holder size, stays identical.
Specifications shown are standard, publicly documented mint figures for each type and era — individual coins vary slightly within normal minting tolerance and circulation wear.
Use it with
- Coin Metal Weight Calculator — break down any total weight and composition you enter, not just the standard specs listed here.
- Coin Holder & Album Size Finder — find the nearest holder size for a diameter you measure yourself.
- Coin Storage & Humidity Guide— turn your own storage space’s humidity and volume into a risk read and desiccant estimate.
- Checking a Coin’s Weight: A First Screen Against Fakes and Alterations — the guide version of the weight-checking logic behind this table.