CD Interest Calculator
See exactly what a certificate of deposit pays by maturity — the interest, the ending balance, and how it stacks up against the national average.
What this calculator actually computes
It grows your deposit by the annual percentage yield across the term, on the assumption that interest stays inside the certificate until maturity — the default setup for most CDs. On $10,000 at 4.40% for 12 months that comes to $440.00 of interest, a maturity value of $10,440, and roughly $36.67 a month on average. That averaging matters: because interest compounds, the later months earn slightly more than the earlier ones, so the monthly figure is a summary rather than a payment schedule.
The one thing it deliberately will not do is convert interest rates. Where your bank quoted you “4.50% compounded daily” instead of an APY, put it through the APY converter first — the difference on that quote is about $10 a year per $10,000, and confusing the two numbers is the single most common CD comparison mistake.
A realistic example: $25,000 for two years
Say $25,000 from a house sale is sitting there and you will not need it until late 2028. A top 24-month CD at 4.25% grows it to $27,170 — $2,170 of interest. The same money at the 1.56% national average for that term earns $786. Closing that $1,384 gap costs you one afternoon spent opening an account at a different bank, which works out to the best hourly rate most people will ever earn.
Two caveats before locking it. First, test the term against your real timeline: breaking that CD at month 8 would cost roughly six months of interest, around $525. Second, if the $25,000 pushes any one institution above $250,000 of your money, split it — insurance limits take no interest in how good the rate was.