CD Calculator Formula & How It Works
- P = CD principal (deposit amount)
- r = Annual percentage yield (APY)
- n = Compounding frequency (usually daily or monthly)
- t = CD term in years
A CD earns compound interest at a guaranteed fixed rate for a set term (3 months to 5 years). The higher the rate and the longer the term, the more interest earned. CDs are FDIC-insured up to $250,000 per depositor per bank and carry no market risk — making them a safe savings vehicle.