The simple interest formula isn't as complicated as the compound formula below. A savings account is an account that earns interest with a financial institution. Let's say you invested $10,000 in ...

Compound interest is interest calculated on both the initial principal and all of the previously accumulated interest. d3sign / Getty Images The formula for calculating simple interest is ...

make sure your account uses simple interest — many accounts use compound interest instead. The formula for simple interest requires your initial principal balance, annual interest rate ...