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CD Calculator

Calculate certificate-of-deposit maturity value and interest from deposit, APY and term in seconds, then open advanced tax, early-withdrawal, comparison and schedule tools when needed.

See what a CD earns at maturity

Enter the opening deposit, advertised APY and term. The maturity value and interest update instantly; no account, rate feed or signup is required.

Quick CD math · browser-local

Opening depositAPYCD term

Value at maturity$10,450.00

$10,000.00 at 4.5% APY for 1 year earns $450.00 and matures at $10,450.00.

Total interest$450.00

Average interest / month$37.50/mo

Monthly-equivalent yield0.3675%

APY basisEffective annual yield

Compare a second APY on the same deposit and term

Second APY

Enter a second APY to compare the same deposit and term.

APY already includes compounding. For APY input, maturity is modeled as deposit × (1 + APY)^{term in years}. Actual bank posting, rounding, withdrawal rules and taxes can differ. This calculator is for scenario math, not a recommendation or live CD-rate quote.

Ready.

Need nominal-rate compounding, taxes, inflation, early withdrawal, comparisons or a month-by-month schedule?Open the inherited CD Decision Studio for those deeper scenarios, local saves, CSV/JSON and portable project links.

Advanced CD Decision Studio APY / nominal rate · tax & inflation · early withdrawal · comparisons · schedule · CSV / JSON

CD decision workspace · APY + after-tax + early-exit scenarios

CD Decision Studio

Model a certificate of deposit from a quoted APY or nominal rate, inspect maturity and monthly growth, estimate after-tax and inflation-adjusted value, then test an early-withdrawal switch before exporting or saving the scenario locally.

Local scenario nameSaved scenario

1. Deposit, rate and term

Use APY when that is what the institution quotes. Choose nominal annual rate only when you also know the compounding frequency.

Deposit ($)Rate (%)Rate isCompounding frequencyTerm (months)Start dateCombined marginal tax rate estimate (%)Inflation assumption (%)

—Maturity value

—Interest earned

—Effective APY

—Maturity date

—After-tax estimate

—Inflation-adjusted after-tax value

—Approx. real after-tax annualized return

—Equivalent nominal rate at selected compounding

—Equivalent monthly rate

2. Growth path

The schedule interpolates the effective annual yield at monthly checkpoints for planning. The on-page table shows the first 12 months plus annual checkpoints and maturity for longer terms; the CSV export contains every month. Institution posting/accrual timing can differ.

Month	Date	Balance	Interest	After-tax est.	Real value est.

3. Early withdrawal & switch test

Enter the institution's penalty assumption yourself, then compare holding to maturity with withdrawing and reinvesting for the remaining original term.

Withdraw after (months)Penalty: months of simple APY-equivalent interestAdditional fixed penalty ($)Replacement APY for remaining term (%)

—Withdrawal date

—Accrued balance

—Estimated penalty

—Estimated net proceeds

—Full-term interest retained after penalty

—Break-even replacement APY

—Switch projected value at original maturity

—Switch advantage / shortfall vs hold

4. Compare three CD scenarios

Use the same deposit, tax and inflation assumptions while varying APY and term. This does not fetch or rank bank offers.

Scenario 1APY (%)Term (months)

Scenario 2APY (%)Term (months)

Scenario 3APY (%)Term (months)

Scenario	Term	APY	Maturity	After-tax est.	Real value est.

5. Report, reuse & portability

Copy the calculation assumptions, export a project JSON, import it later, or make a portable URL. Saved scenarios stay in this browser only.

Model boundary: WebToolArc does not fetch current CD offers or recommend a bank. The tax field is a simple combined marginal-rate estimate, not a tax return calculation. Early-withdrawal formulas, renewal rules and interest posting vary by institution. Deposit insurance depends on institution status, ownership category and other deposits; for insured banks use the FDIC EDIE calculator. Federally insured credit-union share certificates use NCUA share-insurance rules instead; see the NCUA share-insurance guide. The CFPB CD guide explains term and early-withdrawal basics.

Ready.

Core borrowing, saving & investing workflows

Start with the broad calculator that matches the decision, then move to a specialist only when the loan structure, cash flow, tax treatment, debt strategy or savings goal genuinely changes.

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How to use this CD Calculator

Enter the deposit, term, and the rate quoted by the institution. Choose APY when the quoted number is APY; choose nominal rate only when you also know the compounding frequency.

What this calculator does not assume

WebToolArc does not fetch or recommend current CD rates. The result excludes taxes, early-withdrawal penalties, renewal behavior, minimum-deposit rules, and institution-specific insurance eligibility.