How much are U.S. coins 1964 and older worth?

It depends. If it is 1942-1945 zinc coin, several hundred thousand dollars. Otherwise, if it doesn't have an error and is not older that 1900, than just face value.

CorrectionThe previous answer doesn't apply to US Coins in any way.

First, no US coins prior to 1982 were struck in zinc; zinc was only used as plating on cents minted in 1943.

Second, the US has made coins since 1793 at 8 different mints. Higher-denomination coins were made of gold or silver so any that you find today are worth many times their face value simply for their metal content, and among those a substantial number of older dates are worth even more as collectibles.

For example a 1964 time contains about 0.07 troy ounces of silver so if silver is $30 per ounce it has a melt value of around $2 even though 1964 is one of the most common dates for Roosevelt dimes. A 1916-D Mercury dime is a rare collectible; while it also contains the same amount of silver it could possibly be worth thousands of dollars as a collectible.

On the other hand some older Lincoln cents are still so common that more-worn ones can be purchased for a quarter.

The bottom line is that you need to know the coins' dates, mint marks, and compositions to have any idea of values.