CD Calculator

See maturity value and an early-withdrawal penalty. You type the rate as APY or nominal. An estimate, not a bank offer.

Deposit ($) *

Term (months) *

Rate (%) *

Rate type *

Compounding *

Months held if withdrawn early *

Penalty (months of interest) *

Smart Tips

• APY and a nominal rate are not the same number. Pick the one printed on the offer, then pick how often interest compounds.

• The penalty is simple interest on the original deposit: deposit times nominal rate times penalty months divided by 12.

• If you entered APY, the page converts it to a nominal rate at the compounding schedule before it figures the penalty.

• Holding the certificate for zero months still subtracts the penalty from the deposit.

The Formula

Value = Deposit × (1 + nominal ÷ n) ^ (n × months ÷ 12)

APY Annual percentage yield
100 × [(1 + interest ÷ principal) ^ (365 ÷ days) − 1]

n Compounding periods
Per year, or continuous

Penalty Months of simple interest
Deposit × nominal × months ÷ 12

Early Accrued value − penalty
Can fall below the deposit

For a one-year term and annual compounding, a 5% APY grows the deposit by 5%. Continuous compounding uses e raised to the nominal rate times years. The $61.68 example in Regulation DD Appendix A is a 6.17% APY on $1,000 for 365 days.

Key Insights

You supply the rate

This page does not look up certificate rates. The offer you have is the input.

APY versus nominal

A nominal rate still needs a compounding schedule. APY is converted back to nominal before the penalty.

Penalty can touch principal

Banks often take a set number of months of interest even when you have not earned that much yet.

Not a renewal quote

The rate is fixed for the term you enter. A rollover at a new rate is a new calculation.

Frequently Asked Questions

APY is the annual yield after compounding. A nominal rate is the stated rate before that compounding. Regulation DD Appendix A defines APY from interest, principal, and the days in the term. This page also uses the equal-period form (1 + nominal ÷ n) ^ n − 1.

Penalty equals deposit times the nominal annual rate times the penalty months you enter, divided by 12. It is simple interest on the original deposit, not interest on interest. The early value is the accrued value minus that penalty.

Yes. A penalty of several months of interest, taken before much interest has accrued, comes out of principal. The result is still shown. It is an estimate of the agreement you describe, not a bank's legal payoff.

The maturity value is deposit times e raised to nominal rate times years. If you enter APY, the nominal continuous rate is the natural log of 1 plus the APY.

No. You type the rate. There is no rate table and no bank feed. Compare the number on your offer with the value at maturity and the early-withdrawal result.

Maturity value and APY follow Appendix A to 12 CFR Part 1030, Regulation DD, as published by the Consumer Financial Protection Bureau. The general formula is APY = 100 × [(1 + interest ÷ principal) ^ (365 ÷ days in term) − 1]. The worked example there pays $61.68 on $1,000 for 365 days, which is a 6.17% APY. The penalty months are the ones you type. No rate table is used.

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Value at maturity

Enter values to calculate

Interest at maturity

After early withdrawal

Note:This is an estimate from the rate you type. It is not a bank offer, and the penalty months are the ones in your deposit agreement, not a published table. A penalty can be larger than the interest earned.