CD Calculator — Estimate Certificate of Deposit Interest & Maturity

Enter your CD details to see interest earned and maturity value. Private by design—everything runs locally in your browser.

Inputs

Symbol is cosmetic; calculations are unitless.
APY is effective annual yield. APR is nominal; choose compounding below.
For APY, we derive a matching per-period rate using this frequency.

Results

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Formula: \( A = P\,(1+i)^{n} \) where \(i\) is the per-period rate and \(n\) the number of compounding periods. For APY \(e\), \( i = (1+e)^{1/m} - 1 \); for APR \(r\), \( i = r/m \).

How This CD Calculator Works

Thinking about opening a certificate of deposit? This CD calculator helps you estimate how much your money could grow by maturity based on your deposit amount, interest rate, compounding frequency, and term length. It is a quick way to compare CD rates, plan savings goals, or see how different terms affect your total interest.

A certificate of deposit (CD) is a time-based savings product offered by banks and credit unions. You agree to leave your money on deposit for a fixed term, and in return you earn a set interest rate. Unlike a regular savings account, CDs usually pay a higher yield but charge a penalty if you withdraw early. This calculator focuses on the core math: how interest adds up over time and what your balance could be at the end of the term.

How to Use the Calculator

  1. Enter your starting deposit (principal).
  2. Choose whether your rate is APY (effective rate) or APR (nominal rate).
  3. Select the compounding frequency, such as monthly, quarterly, or daily.
  4. Set the term length in years or months.
  5. Click calculate to see the maturity value and total interest earned.
  6. Review the yearly schedule to understand how the balance grows over time.

Example: If you deposit $5,000 in a 12‑month CD at 4.5% APY, the ending balance is slightly above $5,225. If you choose a 24‑month term at the same APY, you earn more interest because your money stays invested longer. The schedule helps you see those increments year by year.

Notes & Assumptions

  • Taxes and bank fees are not included in the estimates.
  • Early withdrawal penalties vary by bank and are not modeled here.
  • For APY, compounding frequency is used to distribute the effective annual growth into per-period rates for scheduling.
  • Results assume no additional deposits or withdrawals during the term.

This tool is helpful when you are comparing CD rates, deciding between APY and APR quotes, or planning a savings ladder. It gives a clear picture of how your savings grow with fixed interest and why term length and compounding matter.

Frequently Asked Questions

What’s the difference between APY and APR?

APY includes compounding over a year (effective rate). APR is nominal—compounding frequency determines the actual yield.

Can I enter partial terms?

Yes—use months or enter decimals in years (e.g., 1.5 years).

Is my data private?

Yes. Calculations run entirely in your browser.

5 Fun Facts about CDs

APY hides the compounding rate

Two CDs can both quote 5% APY, but one might compound daily and the other monthly. The daily one back-solves to a slightly lower nominal rate to reach the same APY.

Rate puzzle

Early withdrawal isn’t always “all interest”

Penalties are often “X months of interest”—not just forfeiting the last months’ earnings. Pulling out early can claw back interest you already earned.

Penalty quirk

Grace periods are short

Most banks give ~7–10 days after maturity to move the money before auto-renewal. Miss it and you might get rolled into a new term you didn’t want.

Timing alert

Ladders are built for surprises

Splitting into staggered CDs (laddering) keeps liquidity: one rung matures soon while others keep earning higher rates.

Liquidity trick

Interest may stop at maturity

If a matured CD auto-moves to checking, growth can halt immediately. Parking in a high-yield savings until you decide can keep earnings alive.

Keep it growing

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