CD Calculator

Q: How is CD interest taxed?

CD interest is taxed as ordinary income at your marginal rate, not the lower long-term capital-gains rate. It's reported on Form 1099-INT for $10 or more, and it's taxed in the year it's earned — so even a multi-year CD that pays out at maturity can create annual tax bills. This tool applies one flat marginal rate to total interest as a simplification.

Q: Is a CD better than a high-yield savings account?

A CD locks in its rate, which is valuable when rates are falling, but the money is locked up and breaking it early triggers a penalty. A high-yield savings account stays liquid but its APY is variable and can drop at any time. Enter a comparison APY to see the dollar difference over the same horizon, and check the early-withdrawal scenario to weigh the liquidity trade-off.

Q: What is an early-withdrawal penalty?

If you cash out a CD before maturity, the bank charges a penalty — commonly a set number of days of simple interest on your principal (often 90 days for terms of a year or less, 180+ days for longer terms). On a very short hold the penalty can exceed the interest you've earned and eat into your principal, which the tool flags.

Q: Is this CD calculator free?

Yes — 100% free. Everything is calculated privately in your browser; nothing is stored or sold. It's an educational estimate, not financial or tax advice.

See what your CD is worth at maturity — after compounding & taxes

Your CD

Initial deposit (principal)

Interest rate (APY)

Rate type

Banks almost always advertise APY — it already includes compounding, so your maturity value is exact regardless of frequency.

Compounding frequency

Term length

Term unit

Most CDs compound daily or monthly. This only changes the result when the rate is entered as APR.

Tax & comparison (optional)

Marginal tax rate (fed + state)

Comparison APY (HYSA / other CD, optional)

Early-withdrawal penalty

CD interest is taxed as ordinary income at your marginal rate — set tax to 0 for pre-tax only. The penalty is the days of simple interest your bank charges for cashing out early (often 90 for ≤1yr terms, 180+ for longer).

Value at maturity

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CD Calculator — guide & how to use

What it does

A certificate of deposit (CD) locks in a guaranteed rate for a fixed term — appealing when you expect rates to fall, but the headline rate isn't what lands in your pocket. This calculator shows what your CD will actually be worth at maturity once compounding and taxes are factored in, computes the effective APY so a 6-month and a 5-year CD can be compared on the same annualized basis, pits the CD against a high-yield savings account (HYSA) or another CD, and quantifies the early-withdrawal penalty so you can weigh the liquidity trade-off. Everything runs privately in your browser, free.

APR vs APY — the most common CD-math error

Banks almost always advertise APY (annual percentage yield), which already includes the effect of compounding. If you enter the rate as APY, your maturity value is exact no matter how often the CD compounds — and changing the compounding dropdown won't change the result (that's correct, not a bug). Only enter the nominal APR if that's the only number you have; then the compounding frequency is applied: A = P × (1 + APR/n)^n×t, where n is periods per year and t is the term in years. Treating an advertised APY as if it were an APR and re-applying compounding double-counts it and overstates your return.

Worked example

$10,000 deposit, 4.00% APY, 12-month term, 22% marginal tax rate, comparison HYSA at 4.00% APY, 90-day early-withdrawal penalty:

Maturity value (pre-tax): $10,000 × (1 + 0.04)¹ = $10,400.00.
Interest earned: $10,400.00 − $10,000 = $400.00.
Tax owed at 22%: $400.00 × 0.22 = $88.00; after-tax interest kept = $312.00.
After-tax maturity value: $10,000 + $312.00 = $10,312.00.
Effective APY: 4.00%; after-tax effective annual yield: ≈ 3.12%.
CD vs HYSA: at the same 4.00% APY over 1 year the maturity values are identical — but the HYSA stays liquid while the CD's rate is locked.
Break it early: the 90-day penalty is simple interest at the nominal rate. A 4.00% APY (daily) is a ~3.922% nominal rate, so the penalty ≈ $10,000 × 0.03922 × (90/365) ≈ $96.71 — a fixed cost charged whenever you break the CD.

(Displayed dollars are rounded to the cent; the tool keeps full precision internally, so hand-rounded steps can differ by a cent.)

How to use it

Enter your deposit, the quoted rate, and pick APY (recommended) or APR.
Set the compounding frequency (only matters for APR) and the term length in months or years.
Add your marginal tax rate to see the after-tax value, a comparison APY to pit the CD against a HYSA or other CD, and an early-withdrawal penalty in days.
Read your maturity value, interest earned, tax owed, effective yields, the comparison, and the break-early scenario.

Accuracy notes & common mistakes

Estimate only — not financial or tax advice. Actual returns depend on your bank's exact compounding method, day-count convention, and crediting rules.
Day-count: this tool uses 365 days/year for daily compounding. Some banks use 365/360 or actual/actual, producing small differences (typically a few dollars over multi-year terms).
Enter APY if your bank advertises one. The maturity value is then exact regardless of compounding frequency. APR + frequency is provided for cases where only a nominal rate is known.
Tax modeling is simplified: one flat marginal rate applied to total interest. In reality CD interest is taxed as ordinary income in the year it's earned/accrued (Form 1099-INT for $10+), even on multi-year CDs — so they create annual tax bills, and your bracket may change year to year.
After-tax effective yield assumes a constant marginal rate across the term; brackets and state rates can change. On a very short term the annualized figure can look large — it's an annualized equivalent, not a guaranteed annual return.
Early-withdrawal penalty is modeled as simple interest on principal over the penalty-day window — a common convention, but check your bank's exact terms. On a short hold the penalty can exceed interest earned and eat into principal.
Don't compare a short CD to a long CD on total dollars — a 5-year CD earns more total interest but may have a lower APY. Compare on effective annual yield instead.
HYSA rates are variable and can fall; the modeled HYSA edge may not hold. The CD's rate is the one that's locked.
Standard CDs are single-deposit — no monthly top-ups. This does not model inflation, FDIC limits ($250k), or promotional/bump-up/callable features.
Context rates (mid-2026: best CD APYs ~4.0–4.3%, HYSA top APYs ~4.0–4.1%, FDIC average savings ~0.38%) move with Fed policy — always enter your own quoted rate.

Frequently asked questions

What will my CD be worth at maturity?

Enter your deposit, rate, and term. If you enter the rate as APY (what banks advertise), the maturity value is principal × (1 + APY)^years — for $10,000 at 4.00% APY for 1 year that's $10,400.00. If you enter a nominal APR, the tool divides it across your compounding periods. Both paths show interest earned and, with a tax rate, the after-tax value.

Should I enter the rate as APR or APY?

Use APY if your bank advertises one — almost all do. APY already includes compounding, so the maturity value is exact regardless of frequency. Only enter APR (the nominal rate) if that's all you have; then the compounding frequency matters and the tool applies it.

Does daily vs monthly compounding make a big difference?

No. At the same APY it makes no difference at all — APY already bakes in compounding. At the same nominal APR the gap between daily and monthly is usually only a few dollars over several years. Term length and rate matter far more.

How is CD interest taxed?

As ordinary income at your marginal rate, not the lower long-term capital-gains rate. It's reported on Form 1099-INT for $10+ and taxed in the year it's earned — so even a multi-year CD can create annual tax bills. This tool applies one flat marginal rate to total interest as a simplification.

Is a CD better than a high-yield savings account?

A CD locks in its rate — valuable when rates are falling — but the money is locked and breaking it early triggers a penalty. A HYSA stays liquid but its APY is variable. Enter a comparison APY to see the dollar difference, and check the early-withdrawal scenario to weigh liquidity.

What is an early-withdrawal penalty?

If you cash out before maturity, the bank charges a penalty — commonly a set number of days of simple interest on principal (often 90 days for ≤1yr terms, 180+ for longer). On a very short hold the penalty can exceed the interest earned and eat into principal, which the tool flags.

Is this CD calculator free?

Yes — 100% free, calculated privately in your browser. Nothing is stored or sold.

Educational estimate only — not financial or tax advice. Compounding method, day-count, crediting, penalty terms, and tax treatment vary by bank and by year; confirm with your bank and a licensed tax professional. CD interest is ordinary income (Form 1099-INT, $10+) taxed as earned. Sources: Bankrate CD calculator & CD/tax guides, Chase "how CD interest is calculated," IRS Topic 403, NerdWallet early-withdrawal penalties.

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