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Free online CD calculator

A certificate of deposit (CD) is a savings account that earns a fixed interest rate over a set term. This calculator shows your final balance, total interest earned, and a monthly.

About this calculator

How to use

  1. Enter the principal — the amount you plan to deposit.
  2. Enter the APY as shown on the bank’s CD offer.
  3. Set the term in months (12 = 1 year, 60 = 5 years).
  4. Choose the compounding frequency (monthly is most common).
  5. The calculator instantly shows final balance, total interest, and a month-by-month table.

The formula

Final Balance = P × (1 + APY / 100)^(t / 12)
Interest = Final Balance − P

Where:

  • P = principal ($)
  • APY = Annual Percentage Yield (%)
  • t = term in months

Because APY already accounts for compounding, this formula gives the correct result regardless of how often the bank compounds internally.

Worked example

You deposit $10,000 in a 12-month CD at 5.00% APY:

  • Final Balance = $10,000 × (1 + 0.05)^(12/12) = $10,000 × 1.05 = $10,500.00
  • Interest earned = $10,500.00 − $10,000 = $500.00

A 24-month CD at 5.5% APY with $10,000:

  • Final Balance = $10,000 × (1.055)^2 = $10,000 × 1.113025 = $11,130.25
  • Interest = $1,130.25

Notes

  • CDs are FDIC-insured up to $250,000 per depositor, per bank.
  • CD rates are typically higher than standard savings accounts because you commit to leaving funds untouched.
  • The month-by-month table shows up to 24 months; for longer terms the final month is also shown.
  • This calculator does not model early withdrawal penalties or taxes on interest income.

Frequently asked

What is a CD?
A certificate of deposit (CD) is a time-deposit savings account offered by banks and credit unions. You agree to leave your money on deposit for a fixed term — typically 3 months to 5 years — in exchange for a guaranteed interest rate. Early withdrawal usually incurs a penalty.
How is CD interest calculated?
This calculator uses the APY (Annual Percentage Yield) directly in the formula: Final Balance = P × (1 + APY)^(t/12), where P is principal and t is term in months. Because APY already accounts for compounding, this formula gives the correct result regardless of how often the bank compounds internally.
What is the difference between APY and APR for CDs?
APY (Annual Percentage Yield) reflects the actual annual return after compounding. APR (Annual Percentage Rate) is the nominal rate before compounding. Banks are required to advertise CD rates as APY under federal Truth in Savings rules, so use the APY figure when comparing accounts.
What happens if I withdraw early?
Most CDs charge an early withdrawal penalty, typically 60–150 days of interest depending on the bank and term. This calculator does not account for early withdrawal penalties — it shows the full interest assuming you hold the CD to maturity.
How do I use the Share button?
Share copies the plain page URL. Share with my numbers copies a URL that includes your inputs as query parameters, so anyone opening the link will see your exact CD scenario.

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