CD Interest Calculator

APY already contains the compounding; APR does not. Enter the rate the way your bank quotes it and pick the matching type — treating an APR as an APY understates the result, and a bank quoting APY is telling you the number that already includes everything.

This calculator turns a deposit, a rate and a term into what a certificate of deposit is worth at maturity — the one figure that says what is actually in the account when the term ends. The interesting part is not the arithmetic but the rate type, because an APY and a nominal rate are two different numbers and the calculator treats them that way. An APY already contains the compounding, so it is simply raised to the power of the term in years: the default 10,000 at 4.5 % APY over twelve months matures at 10,450. A nominal rate is not finished yet. It has to be spread over the periods first, which is why the compounding field exists — and why the APY branch never reads it. The same 4.5 % as a nominal rate reaches 10,460.25 compounded daily and 10,459.40 compounded monthly. Those 85 cents are less than most people expect; against yearly compounding the same deposit differs by 10.25, so the first step in frequency is worth more than every step after it. The result is a gross figure: tax and any early-withdrawal penalty sit outside this calculation. The limitation that matters most is the only one you control — enter the rate the way your bank quotes it and pick the matching type. Treating a nominal rate as an APY understates the result.