Coin Weight Check — Verify Tolerances and Deviations
Traffic Light System
Tips for Weight Checking
- 1. Precision scale with at least 0.01 g accuracy.
- 2. Calibrate scale on a level, stable surface.
- 3. Weigh coin dry and clean.
- 4. Check diameter + thickness with calipers.
- 5. When in doubt, consult a dealer or XRF tester.
Note: The weight test is an initial indication. Professional counterfeits can have correct weights. For reliable authenticity testing: combine weight, dimensions, ring test, and if necessary XRF analysis.
Complete check: Weight + diameter + thickness with overall score.
Check diameter and thickness in isolation.
Melt value for alloys, bars, and jewelry.
Why Weigh Coins?
Weighing a precious metal coin is the simplest and fastest authenticity test that any investor can perform at home. Every mint publishes the exact target weight of its products — if your coin deviates from it, that is an initial warning sign. Unlike elaborate laboratory analyses, you only need a precision scale and a few seconds of time.
The weight check is so effective because counterfeiting the correct weight with a base metal is physically difficult. Every metal has a specific density: gold weighs 19.32 g/cm³, lead only 11.34 g/cm³, and copper 8.96 g/cm³. A counterfeit made of base metal with the correct weight would inevitably have different dimensions — it would be thicker or larger than the original.
How counterfeits are detected
Most common case. Counterfeits made of copper, brass, or zinc cannot reach the target weight because these metals are significantly lighter than gold. Even a 0.5 g deviation on a 1 oz coin is suspicious.
Rarer, but possible. When a counterfeit made from a heavier material like lead (with gold plating) turns out too thick, it can exceed the target weight.
The most sophisticated counterfeit. Weight is correct, but diameter or thickness deviate slightly. That is why you should always check weight together with dimensions.
Important: Weight alone is never sufficient as the sole authenticity test. Always combine the weight check with a dimensional check (diameter and thickness using calipers). Only when both values are correct is the coin very likely genuine.
Weight Check at a Glance
Weighing is the simplest and fastest authenticity test for precious metal coins — you only need a precision scale and a few seconds. For the detailed guide to authenticity testing with all tests, visit our Authenticity Check Guide.
At least 0.01 g resolution, better 0.001 g. From 30 EUR.
Zero the scale with calibration weight before each measurement.
Check weight + dimensions together — tungsten has nearly identical density.
Weight alone is not enough. Tungsten counterfeits achieve correct weight — only dimensional checks (diameter + thickness) and the ring test reliably detect them.
Tolerances for Bullion Coins
No minting is perfect. Every mint specifies official weight tolerances — if your coin falls within this range, it is considered flawless. The variations arise from material feed, die pressure, and temperature.
| Coin | Fineness | Weight | Tolerance |
|---|---|---|---|
|
🇿🇦
Krugerrand
|
916.7‰ | 33.930 g | ±0.070 g |
|
🇨🇦
Maple Leaf
|
999.9‰ | 31.103 g | ±0.030 g |
|
🇦🇹
Philharmonic
|
999.9‰ | 31.103 g | ±0.030 g |
|
🇺🇸
American Eagle
|
916.7‰ | 33.931 g | ±0.060 g |
|
🇬🇧
Britannia
|
999.9‰ | 31.103 g | ±0.030 g |
|
🇺🇸
Gold Buffalo
|
999.9‰ | 31.103 g | ±0.030 g |
All values for 1 oz gold coins. Diameter and thickness can be found in the Authenticity Checker.
Other Authenticity Tests
Weight is only one of several tests. Professional investors combine at least three methods for a reliable result.
Under a loupe (10x–20x), many counterfeits reveal themselves through blurry minting details, incorrect edge notches, or missing security features. Compare the coin with reference images from the mint — pay particular attention to lettering, edge, and color tone.
With a digital caliper (from approx. 15 EUR), you can measure diameter and thickness to 0.01 mm accuracy. Counterfeits with a tungsten core often have the correct weight but deviate in dimensions — this is exactly where dimensional checking complements weight checking.
Genuine gold coins produce a high, clear tone that reverberates for several seconds. Counterfeits sound dull and short. Smartphone apps like "CoinTest" or "Bullion Test" analyze the sound and compare with reference values.
Gold, silver, and platinum are not magnetic. A strong neodymium magnet instantly exposes counterfeits with a ferromagnetic core. With silver coins, an additional effect is visible: the magnet slides slowly over a tilted coin (eddy current effect).
Determines the density of the coin via the water displacement test. Gold has 19.32 g/cm³ — if the value deviates, the coin is suspicious. Also detects tungsten counterfeits, since tungsten (19.25 g/cm³) is slightly lighter.
The most reliable non-destructive method. Many precious metals dealers offer this test free of charge. Limitation: XRF only measures the surface — a gold-plated tungsten core inside is not reliably detected.
Coin Series with Detailed Authenticity Data
For the following 18 coin series, our calculator provides coin-specific counterfeit information — including security features, known counterfeit types, visual authenticity checks, and counterfeit risk assessment. Select a series to load it directly in the calculator above.
Gold Bullion Coins (8)
Silver Bullion Coins (6)
Historical Coins (4)
No data for your coin? Our calculator supports over 129 coins for weight checking. Coin-specific counterfeit information is currently available for the series listed above. For all other coins, the calculator shows general testing tips. We regularly expand the database.