It could vary,but its worth between about $1.50 in Very Fine Condition, $2.50 in Extremely Fine, $4.00 in Amlost Uncirculated and $8 - $60 in Uncirculated
1940 dime were only made from 90% silver. See the related question below for more information.
If it is a circulated dime, then it is worth about $1.00, mostly depending on the value of silver
A 1940 Mercury dime (not Liberty) is very common. If it shows any wear, the value is just for the silver, about $1.90.
Mercury dimes from 1940 to 1945 in average circulated condition are mostly valued for the silver content, about $3.00.
Ten cents was the value of the dime in 1940.
what is the value for an American 1909 silver dime
90% silver, 10% copper.
Assuming the coin is a 1940 Dime a circulated coin is about $2.00 a Mint state coin is $8.00
If you have a 1940 Roosevelt dime it is fake. The Roosevelt dime was not produced by the US Mint until 1946.
They don't exist, the first Roosevelt dime was 1946. With a date of 1940 the dime is a MERCURY dime and is common with average values of $1.00-$3.00 depending on condition.
Mercury dimes from 1940 to 1945 regardless of mintmark's in average circulated condition have the same retail value of $2.00. It may be worth more depending on the grade of the coin.
If it has any wear at all the value is for the silver only about $1.00. A uncirculated 1942 dime is about $2.50