Use our CD Calculator to estimate how your certificate of deposit can grow over time, compare APY versus APR scenarios, and see what happens if you reinvest interest or take it as monthly payouts. In seconds, you can forecast maturity value, total interest, and monthly income potential for any CD term.
What the CD Calculator does
A certificate of deposit (CD) is a time-bound savings product that pays a fixed interest rate for a set term. Because the rate is guaranteed for the duration, CDs are popular for short- to medium-term goals and as a place to earn predictable yield on cash. Our CD Calculator helps you estimate your results based on the size of your initial deposit, the interest rate (as APR or APY), the compounding frequency, and whether interest is reinvested or paid out monthly.
Key inputs and how they affect results
Initial deposit
This is your starting principal. CDs typically do not allow additional contributions after opening, so the initial deposit drives most of the outcome. The larger the deposit, the larger your interest earnings for any given rate and term.
Rate type: APR vs. APY
APR is the nominal annual rate and must be paired with a compounding frequency to determine actual growth. APY is the effective annual yield that already accounts for compounding. If you have APY, you can directly forecast growth without choosing a compounding schedule. When you select APR, the calculator uses your chosen frequency (daily, monthly, quarterly, semiannual, or annual) to compute an equivalent APY and project compound growth.
Compounding frequency
More frequent compounding can slightly boost your ending balance for the same nominal APR. Daily compounding typically yields the highest effective rate for a given APR, while annual compounding yields the lowest. If you select APY, the calculator ignores this setting because APY already embeds compounding.
Term length
CD terms range from a few months to several years. Longer terms generally carry higher rates, but they also lock up your funds. The calculator supports months or years so you can model anything from a 3-month promo to a 5-year CD ladder rung.
Interest payout preference
If you choose to reinvest interest, the balance compounds and your money earns interest on interest. If you choose a monthly payout, the bank pays interest to you as income and the principal stays constant, which is useful for those seeking steady cash flow.
How to interpret the results
- Ending balance: The projected value at maturity when reinvesting interest; with payouts, this equals your starting principal.
- Total interest: The sum of interest earned over the term. For payouts, this is the total of monthly distributions; for reinvestment, it is ending balance minus initial deposit.
- Estimated monthly payout: If you select interest payouts, this shows a typical monthly amount based on your rate type.
- Effective APY: For APR entries, you’ll see an equivalent APY so you can compare offers apples-to-apples.
Practical tips for maximizing your CD returns
- Compare APY, not just APR, to understand true yield.
- Favor daily compounding for the best outcome when rates are quoted as APR.
- Align the term with your liquidity needs to avoid early withdrawal penalties.
- Consider a CD ladder to balance higher yields on longer rungs with rolling access to cash.
- Use the monthly payout option if you want predictable income and don’t need compounding.
Example: Bringing it all together
Suppose you deposit $10,000 for 18 months at 5% APR with monthly compounding and reinvest interest. The calculator will convert APR to an effective APY, apply compounding across the 18-month term, and show your projected ending balance and total interest. If you switch to APY mode at 5.12% and choose monthly payout, it will estimate a monthly payment and total distributed interest while keeping your principal unchanged at maturity. By toggling between these settings, you can quickly see the trade-offs between compounding growth and steady income.
Why use this CD Calculator?
It’s fast, transparent, and flexible. You can model real bank scenarios—promotional rates, daily or monthly compounding, and payout versus reinvestment—so you can make confident decisions before you lock in a term. Whether you’re building a ladder, funding a near-term goal, or simply seeking a safe yield, this CD Calculator puts the numbers at your fingertips.