We've all heard the phrase "that's worth a pretty penny", but how many of us have asked how much a pretty penny is worth. The good thing about the US Mint making a mistake is that it normally comes with some added value. By contrast, small date pennies have noticeably smaller upper loops on their 8s , and the diagonals on their 2s are curved. Mint mark: Once you’ve confirmed the date and font size, you should look for the mint mark. Weight: Finally, you have to confirm that your small date penny is not one of the copper-clad zinc pennies.