I for one prefer the irony that there is much controversy about the namesake of the "Land of Lincoln" and his religious beliefs. The people in the "Land of Lincoln" believe in god, even if it's not conclusive that Lincoln himself did.

I'd thought about a calculator like this for some time, but never coded it.

While you can't account for the weight of the jar (probably negligible anyway--if the jar is a factor, just count the coins by hand), the estimate should be close.

Dimes, quarters and half dollars weigh out the same -- $20 per pound. Pennies ($1.81 per pound) and nickels ($4.53) will lower the average and dollar coins will increase it ($56).

Unless you have a wide fluctuation in the distribution of coins (eg. Lots of pennies on the bottom and dollars on top), you should have a decent approximation.

In my case, I've sorted out pennies and have no half dollars or dollars. I ended up with 150 pounds of nickels, dimes and quarters. My handful is an accurate representation of the total, in my opinion. I ended up with $2500 of coinage. If it were all quarters or dimes (or a combo), I'd have had $3000. As it stands, the $2500 feels about right.

Viewed in another light: I'll take this tool over trying to count $2000+ of coins by hand.