One of the useful things to keep track of in your coin collection (whether you are using a written journal, Excel spreadsheet, or online site like Numista.com to organize your coins) is the quality, or condition, of your coins. It’s helpful to have a good idea about the approximate condition of each coin for a couple of reasons:
When trading, you can more accurately describe your coins and have a better idea about the coins you are trading for
When you find a coin that you already have, you can decide if it is better than the one in your collection
Coin values differ by condition. Knowing your coins’ conditions will help you get more accurate estimates of their value
Coin condition is usually measured on a 70-point scale known as the Sheldon Scale, where 1 represents a coin worn down to almost nothing but a flat circle of metal and 70 represents an absolutely perfect coin. Certain numbers on the scale are given names, such as 1 = Poor, 4 = Good, 8 = Very Good, 20 = Very Fine, 40 = Extremely Fine, and 50 = About Uncirculated. About.com’s Sheldon Scale page gives excellent descriptions of the different grades that you can use to evaluate your own coins on this scale.
Another way to evaluate your coins is to estimate the amount of the original design that is left. The Wikipedia coin grading article has a table called the European Grading System which lists the percentage of detail remaining on the coin for each grade (for example, if there is only 50% of the original detail left on the coin, then it would be considered to be in “Fine” condition).
Luckily, you don’t need to be concerned with all 15 grades in Sheldon’s scale nor the 8 grades in the European Grading System to accurately describe your own coins. For your own collection, just a few different grades should be sufficient:
Good (10% detail remains) – Very worn down but you can still see some of the primary features that were once on the coin
Fine (50% detail remains) – Words and dates are readable but worn; the picture is recognizable but worn
Very Fine (75% detail remains) – Words and dates are clear and show a little wear; the picture is missing some small details (like individual strands of hair on a person’s head)
Extra Fine (90% detail remains) – Words and dates are clear and have sharp edges; the picture has almost all details intact but shows signs of wear
Uncirculated (98-100% detail remains) – Coin shows no sign of wear and has the shine/glow/luster of a new coin (think about how a shiny new penny stands out when you get it back as change)
Left to right: Good, Fine, and Extra Fine estimated condition
(You can shorten this down by combining Very Fine and Extra Fine, so that you have just 4 grades to choose from.)
These 4 or 5 condition grades are fairly easy to judge just by looking at most coins, without even knowing what a perfect coin (with 100% detail) might have. But if you need to compare your coin to another example of the same coin, you can use sites like Numista.com and WorldCoinGallery.com to see pictures of most world coins (note, however, that the coin in the picture may be in better or worse condition than yours). It may be helpful to practice on a big handful of pocket change – sort your local currency by quality into one of the 4 or 5 grades and you’ll get a better feel for what you might consider “Good” versus “Fine” versus “Extra Fine”.
Once you feel more comfortable judging coin quality, you can grade the coins in your own collection (write your condition on the back of the coin flip, and/or add it to your collection tracking information). And you’ll be better able to grade new coins you find, so you can try to replace any “Good” coins in your collection with “Fine” or better.