Bullion verifier · weight, diameter, thickness
Is your gold or silver coin real?
Type what your scale and calipers say. The checker compares each figure with the issuing mint's published specification for 20 common coins and tells you which match, which do not, and what this test cannot catch.
Example · the mint's own figures, typed in
American Silver Eagle, 1 oz·United States Mint
2 of 2 measurements match the United States Mint's figures for the American Silver Eagle, 1 oz.
For silver this is strong evidence. A fake this size at this weight would need a metal with silver's density, and none of the cheap ones (copper, zinc, brass, lead) has it.
Tools this check needs, and the ones that catch what it cannot
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- Digital calipers, 0.01 mm : Diameter and thickness to the precision the spec table is printed at.
- Digital scales with 0.01 g resolution : Weight to a hundredth of a gram; a kitchen scale cannot see a 0.4% shortfall.
- Electronic precious-metal verifiers : Conductivity through the coin: the one home test that catches a tungsten core.
- Acid test kits : A scratch test for surface purity when the piece is not a listed coin.
- Neodymium slide magnets : Silver slows a strong magnet sliding down its face; steel and plated blanks do not.
Published specifications, 20 coins
as printed by the issuing mints · reviewed 2026-09-14| Coin | Metal | Fineness | Weight, g | Diameter, mm | Thickness, mm | Source |
|---|---|---|---|---|---|---|
| American Gold Eagle 1 oz | Gold | .9167 | 33.931 | 32.70 | · | United States Mint |
| American Gold Eagle 1/2 oz | Gold | .9167 | 16.966 | 27.00 | · | United States Mint |
| American Gold Eagle 1/4 oz | Gold | .9167 | 8.482* | 22.00 | · | United States Mint |
| American Gold Eagle 1/10 oz | Gold | .9167 | 3.393* | 16.50 | · | United States Mint |
| American Gold Buffalo 1 oz | Gold | .9999 | 31.103 | 32.70 | · | United States Mint |
| Canadian Gold Maple Leaf 1 oz | Gold | .9999 | 31.110 | 30.00 | · | Royal Canadian Mint |
| Gold Britannia 1 oz | Gold | .9999 | 31.107* | 32.69 | · | The Royal Mint |
| Krugerrand 1 oz | Gold | .9167 | 33.930 | 32.69 | · | Rand Refinery (realkrugerrand.com) |
| Vienna Philharmonic 1 oz gold | Gold | .9999 | 31.103* | 37.00 | · | Austrian Mint |
| Australian Kangaroo 1 oz gold | Gold | .9999 | 31.107 min | 32.60 max | 2.95 max | The Perth Mint |
| American Silver Eagle 1 oz | Silver | .999 | 31.103 | 40.60 | · | United States Mint |
| Canadian Silver Maple Leaf 1 oz | Silver | .9999 | 31.110 | 38.00 | · | Royal Canadian Mint |
| Silver Britannia 1 oz | Silver | .999 | 31.135* | 38.61 | · | The Royal Mint |
| Vienna Philharmonic 1 oz silver | Silver | .999 | 31.100 | 37.00 | · | Austrian Mint |
| Australian Kookaburra 1 oz silver | Silver | .9999 | 31.107 min | 40.90 max | 3.50 max | The Perth Mint |
| Mexican Libertad 1 oz silver | Silver | .999 | 31.135* | 40.00 | · | Banco de México |
| Morgan / Peace silver dollar 90% silver, 1878 to 1935 | Silver | .9 | 26.730* | 38.10 | · | Act of February 28, 1878 (govinfo.gov) |
| Kennedy / Franklin / Walking Liberty half dollar 90% silver, 1964 and earlier | Silver | .9 | 12.500 | 30.61 | · | Coinage Act of 1873, s.15 (govinfo.gov) |
| Washington quarter 90% silver, 1964 and earlier | Silver | .9 | 6.250 | 24.26 | · | Coinage Act of 1873, s.15 (govinfo.gov) |
| Roosevelt / Mercury dime 90% silver, 1964 and earlier | Silver | .9 | 2.500 | 17.91 | · | Coinage Act of 1873, s.15 (govinfo.gov) |
* The mint prints fine-metal content only; the gross weight is that content divided by the fineness. A dot means the mint publishes no thickness (none does except The Perth Mint, whose diameter and thickness are maxima and whose weight is a minimum). Pre-1965 US silver weights are the statutes' figures; the Mint's own page covers only coins in production.
How to measure, and what this check cannot catch
Weight. A 0.01 g scale, tared, coin flat in the centre. Genuine coins are struck at or above the mint's figure (the United States Mint prints the Silver Eagle's weight as a minimum), so a shortfall of even half a percent is the thing to look at. Plated copper, zinc and brass fakes come in 10 to 30% light.
Diameter and thickness. Digital calipers, jaws square to the rim, read twice at right angles. Thickness is the least repeatable figure: the rim is thicker than the field, and the jaws must land on the rim both times. That is why the thickness line is the widest.
What passes this check and is still fake. A tungsten-cored gold coin. Tungsten's density is 19.25 g/cm3 against gold's 19.32, under 0.4% apart, so a fake struck to size weighs right and measures right. The tests that see through the surface are conductivity (an electronic verifier), ultrasound, and to a lesser degree the ping of the coin. Silver has no such twin among cheap metals: copper (8.96), zinc (7.13) and brass are far lighter, lead (11.34) is 8% heavier, so for silver the three measurements together are strong evidence.
What this checker does not do. It does not compute density from your measurements. A coin's true volume is well under its bounding cylinder, so weight divided by pi r² h reads 5 to 10% low on every genuine coin and would flag them all. It compares the three published dimensions one by one instead. It does not cover bars, rounds or coins not in the table.
Frequently asked questions
- How can I tell if a silver coin is real at home?
- Weigh it on a 0.01 g scale and measure its diameter and thickness with calipers, then compare all three to the mint's published figures. Silver has a density no cheap metal shares, so a coin that is the right size and the right weight is very hard to fake. A strong neodymium magnet should slide slowly down a tilted silver coin rather than stick or drop, and a real coin rings when balanced on a fingertip and tapped.
- Can a tungsten-filled gold coin pass a weight and size check?
- Yes. Tungsten's density is 19.25 g/cm3 against gold's 19.32, a difference of under 0.4%, so a plated tungsten blank struck to the right dimensions weighs what the mint says. A scale and calipers cannot see it. An electronic conductivity tester such as the Sigma Metalytics verifier reads through the surface and does; an ultrasonic thickness gauge or a ping test also catch most of them.
More questions
- How much does an American Silver Eagle weigh?
- The United States Mint lists the American Silver Eagle at 31.103 g (one troy ounce) of .999 fine silver and 40.60 mm in diameter. The Mint publishes no thickness for it; the 2.98 mm on dealer sheets is a measurement, not a specification. Genuine coins weigh the Mint's figure or a little more, never less.
- What tolerance does this checker use?
- The mints publish no tolerances, so these are The Vault Report's, set from the spread seen on genuine coins with a 0.01 g scale and 0.01 mm calipers: a weight more than 0.4% under the mint's figure or more than 1.5% over it is flagged, a diameter more than 0.15 mm off, and a thickness more than 0.25 mm off. Circulated 90% silver gets a 4% allowance for wear. Where a mint publishes a maximum rather than a nominal (The Perth Mint), only an excess is flagged.
- Why do old 90% silver coins weigh less than the mint's figure?
- Wear. A Morgan dollar or a pre-1965 quarter that circulated for decades has lost a few percent of its metal to pocket friction, and it is still every bit real. The checker widens the underweight line for those coins. A modern bullion coin has never circulated, so the same shortfall on a Silver Eagle is a flag.
- What does the magnet slide test show?
- Silver and gold are not magnetic, but they are good conductors, so a strong magnet sliding down a tilted coin induces eddy currents that brake it: it drifts down slowly. On a steel blank the magnet sticks; on a plated zinc or copper blank it drops at normal speed. It is a quick screen, not a verdict, and a tungsten-cored gold coin passes it.
Valuing scrap instead? The scrap calculator prices it at spot