Compare certificate of deposit offers
Apply each bank’s quoted APY and term to the same deposit before comparing liquidity and penalty terms.
CD Interest Calculator
Enter a deposit, quoted APY, term, and optional months-of-interest penalty to project your certificate of deposit balance instantly.
Financial Calculators
Calculate CD Interest from APY
APY already includes compounding. Enter the quoted APY, deposit, and term to estimate maturity value.
Your CD interest estimate will appear here
Enter a deposit, APY, and term; results update automatically.
This is a projection, not a bank quote. APY, withdrawal rules, penalty calculation, rounding, taxes, and renewal terms vary by institution. Confirm the account disclosure before depositing or withdrawing.
What Is CD Interest Calculator?
A CD interest calculator projects how a fixed opening deposit may grow over a certificate of deposit term. This page treats the bank’s quoted annual percentage yield, or APY, as an effective annual return, so you do not select a separate compounding frequency.
The optional penalty field converts months of simple interest into a planning deduction. Real banks may use a different balance, rate, day count, minimum penalty, or principal-reduction rule, so the account disclosure controls.
How to Use CD Interest Calculator
1
Enter the Opening Deposit
Use the principal that will remain in the CD without additional contributions.
2
Add the Quoted APY and Term
Copy the APY from the account disclosure and enter the term in months.
3
Model an Optional Penalty
Enter months of interest only when the bank describes its penalty that way.
4
Review the Live Projection
Compare maturity value, earned interest, and the penalty-adjusted planning balance.
How the CD Interest Calculator Works
APY represents annual growth after compounding. The calculator raises one plus APY to the term in years and multiplies by the opening principal.
The optional penalty is estimated as simple interest on the original principal for the entered number of months.
Maturity = principal × (1 + APY)^(months ÷ 12); penalty estimate = principal × APY × penalty months ÷ 12
Example
A $10,000 deposit at 4.50% APY for 12 months grows to $10,450.00 and earns $450.00. A three-month simple-interest penalty estimate is $112.50, leaving $10,337.50.
CD Interest Calculator Features
- Correct APY-based growth without double-counting compounding
- Terms from 1 to 120 months
- Separate maturity value, interest, and penalty-adjusted balance
- Live results with the active formulas shown
Common Use Cases
Estimate an early withdrawal
Enter the stated months-of-interest penalty for a rough balance, then verify the bank’s actual calculation.
Limits and Important Notes
- Actual APY, daily accrual, maturity dates, rounding, and renewal rules come from the bank’s disclosure.
- The penalty model may not match a bank that uses earned interest, current balance, minimum days, or principal forfeiture.
- Income tax, inflation, fees, insurance limits, rate changes on variable products, and additional deposits are excluded.
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