What does a silver US dime weigh?

Silver US dimes minted from 1873 to 1964 weighed 2.5 grams when new. The coins were made of an alloy of 90% silver and 10% copper, so they contain 2.25 gm of pure silver.

Silver dimes with earlier dates weighed different amounts due to adjustments in the price of silver.

When silver prices were deregulated and the composition of dimes, quarters, and halves was changed to copper-nickel, the weight of the dime was reduced to 2.27 grams to maintain the same diameter and thickness.