It would be worth zillions - there were no half dollars struck with that date.
All halves, quarters, and dollars struck in 1975 and 1976 carried the dates 1776-1976 in honor of the Bicentennial.
Please post a new, separate question. JFK is on the US half dollar. George Washington is on the US quarter.
It's worth exactly 25 cents.
It's either not a quarter or not Kennedy. JFK's picture is on the half dollar. Washington is on the quarter, where he's been for about 80 years. Either way these are common coins left over from the Bicentennial. In circulated condition they're only worth face value or a couple of extra cents.
The value of a 1981 quarter dollar primarily depends on its condition and whether it is a standard circulation coin or a special variety, such as a proof coin. Generally, a regular 1981 quarter in average circulated condition is worth face value, 25 cents. However, uncirculated or proof versions may have a higher collectible value, typically ranging from a few dollars to more, depending on specific grading and demand among collectors. Always check current market trends for the most accurate valuation.
Check that coin again. Mint marks were on all quarters by 1981.
Darren Kennedy was born in 1981.
If your coin says "QUARTER DOLLAR" on the back it's a Washington quarter and is worth only 25¢ John F. Kennedy lived in the 20th century and would not be wearing a powdered wig!If your coin says "HALF DOLLAR" on the back it's a halfdollar and is worth extra for its silver content. There's more information at the Related Question.
The cast of Grace Kennedy - 1981 includes: Ian Charleson as Himself - Singer Grace Kennedy as Herself - Host
Washington is on the quarter, and Kennedy is on the half. Whichever coin you mean, it's worth face value.
Nick Kennedy was born on 1981-08-19.
All error coins need to be seen for an accurate value. Take it to a local coin dealer for an assessment.
All circulation 1971 and later halves are made of copper-nickel, not silver, so they have no added value if you found it in change. A nice uncirculated 1981-P half might bring $1 to $8 depending on quality. A 1981-D would be $1 to $12.