While many people might think that nickels are simply smaller versions of quarters, they are actually a bit different. For one, quarters are 20 mm in diameter while nickels are 21.21 mm. This might not seem like much of a difference, but it means that nickels are actually slightly larger than quarters. In terms of inches, this means that quarters are about 0.79 inches in diameter while nickels are about 0.835 inches in diameter. So if you're trying to figure out how many inches there are in a nickel, the answer is slightly more than three-quarters of an inch.