What is the value of John F. Kennedy memorial half dollar 1917-1963?

Answer 1

There were no circulating half dollars struck with his dates of birth and death. You probably have something that was made outside of the mint, or is a regular half dollar that's had the dates added by a private company. That means it's an altered coin with no extra value beyond its metal content, which could be:

90% silver (1964)

40% silver (1965-70)

Copper-nickel (no added value, 1971-present)

Answer 2

Kennedy halves that year were 40% silver, and currently worth about $5.