How Do You Assign Value For In Between Grades?

You could be a real geek(like me sometimes) and plot values at the standard grades on an XY graph and then mathematically interpolate the values for the in-between grades. However, most normal people just wing it and split the difference between the grades and values, i.e. a VF30 would be worth the VF20 value plus 50% of the difference in value between VF20 and EF40.

Obviously, coming up with a precise number through mathematics is not really necessary for lower value coins where a guesstimate works just fine but if you are dealing with hundreds or thousands of dollars, it can be a worthwhile exercise

In looking at lots of pricing and "gut instinct" I came up with a simple formula a couple years ago that seems to work pretty well (at least for me).

One third the difference of the value of the full grade increase.

So if the F-12 price is $30 and the VF-20 price is $60, the F-15 price is $40 (it went up $30 from one grade to the next, so add $10 for the split grade).

Going up by half the value makes a certain amount of mathematical sense, but doesn't seem to hold up in real-world pricing. (I've not even tried to come up with a formula for VF-25/30/35 incremental pricing.)

Considering how "main stream" these in-between grades have become in recent years, I'm surprised RedBook, Greysheet, and other pricing guides have not begun listing prices for VG-10, F-15, VF-30, etc. 'Coin Values' has begun the process, putting some of these columns into their published prices guides, but it seems to have become a big project for them to get these columns populated with values.

It's really simple. You go to a copy of the Red Book, look up a coin in both those grades, write down the prices. Then go to the PCGS forum's price listing and do the same. Now you go to ebay, look up that same coin and in those same grades and again, write down the prices. Now you contact a few on line con dealers and request their prices on that coin in those same grades and then again, write down those prices. Next you get a copy of the grey sheet and look up that coin in those grades and write those down.
Now with all that info, add up all the prices in each catagory, divide by the number of entrees and you should now have two averages of numerous different sources for that coin in two different grades.
So now you take those two numbers, add together, divide by two and then the final step.
Ask someone here how much it is worth.

For a more serious answer if I were you I wouldn't worry about the value unless your planning on selling that or any coin. But if you really are interested the thing to remember is there is really no exact method in appraising a coin except what someone is wiiling to pay for it. You could assume a coin is worth a hundred dollars but if the only amount you could get if offered for sale was ten dollars, then it is worth ten dollars.
If you just want a guessamated, just made up that word, value I'd say just go to about 2/3rds the distance from the first value to the second knowing coins usually jump somewhat in that proportion between higher grades.

I do think that whatever formula you use, the split grade coin is going to be closer to the value of the lower "full grade" than to the higher. So a VG-10 coin's value will be closer to VG-8 in value than to F-12.

The one exception might be VF-35. In my opinion, this might be in the middle, half way between the values of a VF-20 and an EF-40, but I could be convinced that it might be a bit higher than that.

Those were the days!

It was nice when a coin was simply "uncirculated" without 11 options of exactly "how uncirculated" it was.