CD Calculator
Use this CD calculator to see how much interest a certificate of deposit earns by maturity. Enter your deposit, the rate as APY or APR and the term in months. You can also test what an early withdrawal penalty would cost and how much of the interest is left after tax, with the balance shown month by month or year by year.
Updated
Results
- APYAnnual percentage yield
- APRNominal rate at the chosen compounding
- Tax on interestShown when you enter a tax rate
- Interest after tax
- Amount received if withdrawn earlyDeposit plus interest minus penalty
- Early withdrawal penalty
- Interest kept after penaltyNegative means you lose part of your deposit
| Month | Interest to date | Balance |
|---|
Results are estimates. See the methodology below.
How to use the CD calculator
- Deposit: the amount you put in the CD.
- Rate: choose APY (annual percentage yield, the figure banks advertise, which already includes compounding) or APR, the nominal interest rate, and pick how often interest compounds.
- Term: the length of the CD in months, from 1 to 120.
- Early withdrawal: tick the box, then enter the month you'd cash out and the penalty in months of interest from your deposit agreement.
- Tax rate (advanced): your combined tax rate on interest, if you want an after-tax figure.
The tax and early withdrawal results appear only when you fill in those fields.
How the calculator works
APY and APR are linked by the compounding frequency k (365 for daily, 12, 4, 2 or 1):
APY = (1 + APR ÷ k)^k − 1
If you enter an APY, the compounding choice only changes the equivalent APR shown; the growth is the same. The balance after t months is:
Balance = deposit × (1 + APY)^(t ÷ 12)
Interest stays in the CD until maturity; no payouts are taken along the way.
Early withdrawal: the penalty is modeled as N months of simple interest on the deposit, deposit × APR × N ÷ 12, subtracted from the interest earned so far. Banks' formulas vary: some count days, some charge only on the amount withdrawn, so check your deposit agreement.
Examples
1. $10,000 for 12 months at 4.10% APY
You earn $410.00 and the CD matures at $10,410.00. With daily compounding that APY equals an APR of 4.018%. At a 22% tax rate, $90.20 goes to tax and $319.80 is left.
2. Same 4% APR, different compounding
| Compounding | APY | Interest on $10,000, 12 months |
|---|---|---|
| Daily | 4.081% | $408.08 |
| Monthly | 4.074% | $407.42 |
| Quarterly | 4.060% | $406.04 |
| Annually | 4.000% | $400.00 |
This is why comparing APYs is easier than comparing APRs.
3. Cashing out early
From example 1, withdrawing at month 6 with a 3-month penalty costs $100.46, leaving $102.48 of interest. Withdrawing at month 1 with a 6-month penalty costs $200.92, more than you earned: net interest is −$167.38 and you get back $9,832.62, less than you deposited.
On a 5-year, $25,000 CD at 3.8% APY, interest at maturity is $5,124.98. Breaking it at month 24 with a 12-month penalty costs $932.44 and leaves you $1,003.66 of interest.
How to read your results
Most CDs pay a fixed rate for the whole term, so the interest shown is what you earn if you hold to maturity. The real trade-off is access to your money: before choosing a longer term for a higher APY, check the penalty and run the early withdrawal scenario. Some savers split money across several CDs with staggered maturities, called a ladder, so that part of it becomes available regularly; this calculator models one CD at a time.
Frequently asked questions
What's the difference between APY and APR on a CD?
APR (or interest rate) is the nominal yearly rate; APY includes the effect of compounding over a year. For the same APR, more frequent compounding gives a higher APY. If a bank quotes both, use the APY to compare offers.
Is CD interest taxable?
Yes. The IRS lists interest on certificates of deposit as taxable income, and banks send Form 1099-INT if you receive $10 or more. You must report the interest even without the form. CDs longer than one year can follow special timing rules described in IRS Publication 550.
Is an early withdrawal penalty tax-deductible?
On the 2025 Schedule 1 (Form 1040), the penalty on early withdrawal of savings is an adjustment to income (line 18), so you don't need to itemize to claim it. You still report the full interest credited to you.
Are CDs insured?
CDs at FDIC-insured banks are covered up to $250,000 per depositor, per insured bank, for each account ownership category. Credit union share certificates are insured by the NCUA up to $250,000. Since April 1, 2024, trust accounts are capped at $1,250,000 per owner per bank, reached with five or more beneficiaries.
Can I lose money in a CD?
Held to maturity at an insured institution within the limits, no. Early withdrawal is the main risk: as example 3 shows, a penalty can exceed the interest earned and eat into your deposit.
Sources
This calculator provides estimates for educational purposes and is not financial or tax advice. Your bank's terms, including how interest and penalties are calculated, determine the actual amounts.