Precious Coin Tester

How to tell if a gold coin is real?
How to test silver coins to avoid buying fakes?

Precious coin tester is here to help you!

What is it?

Precious coin tester is a free application which helps to detect fake gold/silver coins. A user knocks the coin with another hard object (another coin, a key, etc..), and the app provides you the result. The limitations of the app are as follows:

  • It can be only used to test round gold/silver coins without hole.
  • It can only test the content of precious metal in the coin. The app cannot distinguish a fake coin of similar or the same percentage of precious metal from the real, original one.
  • Minimum fineness requirement: gold 7%, silver 20%; result might be inaccurate if gold <20% or silver <50%.

How to use?


Tester page

User input

  • Fineness(%): The nominal fineness of the coin.
  • Weight(g): The real weight of the coin in grams, the nominal weight is also acceptable.
  • Diameter(mm): The real diameter of the coin in millimeters, the nominal diameter may have large errors (>0.5mm).

User action

  • Check: Start a new test by acquiring the sound of coin.
  • Replay: Replay the last test.


  • Progress bar: Show the progress of current sound acquirement/replay.
  • Summary: Show summary info before analysis and show the result after analysis.
  • Sound view: Show the acquired sound.

Catalog page

User input

  • Year: Year of mint.
  • Keyword: keyword search.
  • Others: choose coin type, region of issuers*

*Regions are defined according to UN Geographic Regions (check list of regions).

User action

  • After inputs changes, if the result list contains

    • 0 - 7 coins: list will automatically displayed,
    • 8 - 100 coins: click 🔍 to display the result,
    • > 100 coins: too many results, please refine the search.
  • Double click on a coin to return to tester view.

  • Click on information button (ℹ️) to get more details of the coin from Numista website.

Run a test

  1. Open the app, enter the nominal fineness, weight and size of the coin, or directly select a coin from catalog.
  2. Click on Check to start the analysis.
  3. While the progress bar growing, hold the coin on the tip of one finger, and knock the coin rapidely with another hard object near the mic of your phone/tablet.
  4. The coin generates its own sound after the knock. Hold still the coin while it rings.
  5. When the sound of coin has diminished, knock it again.
  6. Repeat Step 5 until the progress bar finishes.

Please watch demonstration.

Read the result

Three stars show the quality of your coin:
(3/3): The coin passes the test: the precious metal content is almost the same as its nominal value (only reserved for coins selected from catalog).
(2/3): The coin passes the test: the precious metal content is close to its nominal value.
(1/3): The coin may pass the test: the precious metal content is probably different from its nominal value, or the actual diameter and weight may be different from the nominal values.
(0/3): The coin fails the test.

Unstable result: Please test again as the sound quality is poor. We are not sure about the result.

Replay the last test

You can reply the last test by clicking on the Replay button on the interface.

Want a try without any silver/gold coin?

Youtubers can help!
For example, in this video
[1:47] Real silver eagle: got 3 stars from app
[1:59] Fake silver eagle: got 0 star unstable result from app
[6:52] 50 doller gold eagle (by guessing from image): got 2 stars from app
Since the quality of sould in videos is not as good as real tests, you may have frequently “unstable result”.
More examples.

How does it work?

Each object has its own proper sound. This sound depends on various characteristics of the object.
Coins have their special sound as well. The app collects the sound generated by the coin under test, and analyse the coherence between this sound and the information provided by the user. The level of the coherence is returned as result.

More explanation in this video


Is it secure to use the application?

Yes. The application neither askes for your personal data nor uses GPS information. It needs only microphone and writing to storage permissions. As protocol, IP address is publicly available to the whole internet. If you feel uncomfortable with it, a VPN can be used to mask your true IP address.

Why it does not work on my device?

There are different configurations on some devices and the application may not cover all of them. Please don’t hesitate to contact us, we try to fix the problem as soon as possible.


By downloading, accessing or using Precious coin tester app or any page of this app, you signify your assent to this disclaimer. The contents of this app, including without limitation, all data, information, text, graphics, and other materials are provided as a convenience to our app users and are meant to be used for informational purposes only. We do not take responsiblity for decisions taken by the user based on the information provied in this app.

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