Which US half dollars are worth anything?

To be very technical, all US half dollars are worth at least 50 cents. If you're referring to those half dollars that are worth MORE than face value, the general rule is that any half dated 1971 or later doesn't have any extra value, but those with earlier dates contain silver so they're definitely worth a premium:

> Halves dated 1965 to 1970 were made from 40% silver so they're worth about 1/7 the current price of an ounce of silver. Except for 1970 coins that were sold only to collectors, these dates don't generally have any extra collector value.

> Halves dated 1964 and earlier are 90% silver so they're worth about 1/3 the price of an ounce of silver at a minimum. Older dates (1940 and before) very often are worth even more to collectors but you need to know their specific dates and mint marks.