How This Calculator Works
A Certificate of Deposit pays a fixed rate for a fixed term using the standard compound-interest formula: Maturity Value = Principal × (1 + r/n)n×t, where r is the annual rate as a decimal, n is how many times per year interest compounds, and t is the term in years. This calculator applies that formula directly to your deposit, rate, compounding frequency, and term.
What Actually Makes a CD Different
The defining trade-off of a CD is simple: you lock in today's rate for the entire term, and in exchange you give up easy access to that money until maturity. If rates rise after you open the CD, you're stuck at the lower locked-in rate; if rates fall, you're protected and keep earning the higher rate you locked in. A savings account moves with the market in both directions and never restricts withdrawals, but it offers no such rate guarantee.
Same Rate, Real Difference: Compounding Frequency
Take a $10,000 deposit at a flat 5% annual rate for one year. Compounded annually, it earns exactly $500.00 in interest. Compounded monthly, that same 5% earns $511.62. Compounded daily, it earns $512.68. The gap between annual and daily compounding here is only about $12.68 — small, but real, and it comes entirely from interest being calculated and added back into the balance more often, so subsequent interest is earned on a slightly larger base each time. The comparison table above runs this same math against your own numbers.
CD Laddering, Briefly
Instead of putting one lump sum into a single 5-year CD, laddering splits it across several CDs of different terms — say, 1, 2, 3, 4, and 5 years. Every year, one rung matures, and you can either spend that money or roll it into a new long-term CD at whatever rate is then available. The benefit is a rolling source of liquidity without giving up CD-level rates on the rest of your money. It's a reasonable middle-ground strategy, not a way to beat the market — you're still accepting a locked rate on most of your balance at any given time, just spread across staggered maturities instead of one.
Worked Example
$10,000 deposited at 5% APY, compounded monthly, for a 12-month term: Maturity Value = $10,000 × (1 + 0.05/12)12 = $10,511.62, meaning $511.62 in total interest earned over the year.
Related Tools
To model compound growth outside the fixed-term structure of a CD, try the Compound Interest Calculator. If you're saving toward a specific dollar target rather than starting from a lump sum, the Savings Goal Calculator works backward from that goal. And for a quick comparison against non-compounding interest, see the Simple Interest Calculator.
Disclaimer: This calculator and guide are for educational purposes only and should not be considered financial advice. Always consult with a qualified financial advisor before making investment decisions. Past performance does not guarantee future results, and all investments carry risk.