U.S. Coin Counter, Weight to Value

Do you have a large number of coins (nickels, dimes, quarters, and/or half dollars) you need to count quickly? Some stores have a change counting machine, but these often charge for their service, usually 8 cents per dollar. The service below is completely free, all you need is a gram scale and this page.

Measure the weight of your change using a gram scale with 4 decimal point precision. Enter the value below. If you're counting a large number of coins you may also need to increase the maximum iterations. Note: due to ambiguities, cents (pennies) cannot be counted here, neither can Sacagawea or SBA or Eisenhower dollars. Remove copper-colored coins before weighing. JavaScript must be enabled in your browser.

Weight: grams
Maximum iterations:

Dimes: (quarters=2.5, halfs=5)
Value: $

There is a TI-89 version of this program also, useful when a calculator is available but not a web browser.

More Information...

What is "ERR: Not found" and how can I fix it?

This means the weight you entered does not correspond to the weight of a collection of U.S. coins. 4-decimal point precision and accuracy is necessary for the value to be calculated correctly. A dime weighs 2.268 g; if you enter mistakenly 2.269 g, an error will occur.

If you're counting a large amount of change, the maximum iterations may need to be increased to a larger value. Do this if you know your measurements are accurate and yet "ERR: Not found" still occurs.

On the TI-89 version, there is no limit on maximum iterations. Incorrect weights will cause coincnt() to run until the calculator overflows. Use "On" to cancel coincnt if this occurs.

What commercial services are available to cash in coins?

CoinStar will do it for a fee. Depending on how much your time is worth, it may be cheaper to buy coin rolls and turn them into your local bank.

How does this work, why aren't pennies counted?

Before 1964, most U.S. coins were silver. Coins derived their value directly from the metallic content. 0.2268 grams of silver was worth $0.01. Therefore a dime was 2.268 grams of silver, a quarter 5.670 grams, and half dollar 11.340 grams. After '64 coins were no longer silver, yet this historical artifact remains.

Lincoln cents weigh 2.5000 grams/cent, nickels 1.000 gram/cent. So 5 grams could be either 2 cents or 1 nickel (5 cents). This ambiguity is why pennies are not counted.

Thus the coins can be calculated by solving for W = 2.268*D + 5.000*N, where W=total weight, D=number of dimes, and N=number of nickels. An iterative process is used to do this. Once D and N are known, the value can be calculated by A = $0.10*D + $0.05*N.

Isn't "mass" a more correct term than "weight" to describe the measurement of heaviness of the coins in grams?

Yes. Weight is the force due to gravity, mass is the amount of matter, independent of gravity.

  Mass Weight
Imperial slugs pounds
Metric kilograms newtons

But the distinction is minor except to physicists.

Contact information?

coincnt at xyzzy.cjb dot net. Feel free to email me if you have any questions or comments about the JavaScript or TI-89 coincnt.


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Modified Sun Mar 25 08:48:47 2007 generated Sun Mar 25 08:56:33 2007