A CD locks in a fixed rate for a fixed term. Interest is calculated and added to your balance at set intervals — daily, monthly, quarterly, semiannually, or annually — and each addition then earns interest itself. More frequent compounding produces a higher effective yield from the same stated rate, which is why two CDs quoting the same interest rate can still mature to different amounts.
Most CDs reinvest interest automatically, so it compounds along with your principal. Some banks let you have interest paid out each period instead — useful for supplementing income, such as in retirement — but that withdrawn interest no longer compounds, so it grows as simple interest and produces a lower total return than the same rate reinvested. Switch Interest Payout to "Paid Out" to compare the two.
CDs trade flexibility for a fixed rate: withdrawing before maturity usually triggers a penalty, commonly a set number of months of interest rather than a flat fee. That penalty is typically deducted from interest already earned, not from your principal. Use Penalty mode to see the net value if you break the CD early.
Most CDs accept a single deposit and then close to new money for the whole term. An add-on CD is the exception: it lets you keep paying into the same certificate at the locked-in rate, which is worth having when rates are falling and you would rather not open a new CD at a lower one. Each deposit only earns interest for the time it is actually invested, so a deposit made in the final month adds very little — the Add-On mode counts deposits at the end of each period and shows how many of them the term actually contains.
A ladder splits one deposit across several CDs with staggered maturity dates instead of locking it all into a single term. As each rung matures, you get periodic access to a portion of your money and can reinvest at then-current rates, which reduces the risk of locking your entire balance into one rate for one long term. Use Ladder mode to model how many rungs and what maturity spacing works for your timeline.
Maturity Value: Final value with compounded interest.
Interest Earned: Total interest over the term.
Effective Rate (APY): Accounts for compounding.
Early Withdrawal: Calculate penalty impact.
Growth Chart: Visualize value over time.
CD Ladder Planning: Split one deposit across multiple staggered maturities.
Interest Payout: Choose reinvested (compounding) or paid-out (simple interest) growth.
Add-On CD: Model extra deposits paid in during the term, monthly, quarterly or annually.
Investment Planning: enter principal, term, and rate to see maturity value and interest earned, choosing a compounding frequency (e.g. monthly, quarterly).
Savings Goals: set a target amount to see which term or rate gets you there, and compare CD growth to other savings options.
Early Withdrawal Analysis: see the impact of early withdrawal (e.g. penalty) on returns and decide whether to break the CD or keep to term.
Rate Comparison: re-run with different terms and APY offers to compare maturity value, and export or copy results for records.
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