CD Calculator
Calculate what a certificate of deposit pays at maturity.
- Author
- CentCompass Research Team
- Reviewed by
- Editorial Review
- Last Updated
- Reading Time
- 4 min read
Value at maturity
$10,425.00
Interest earned
$425.00
Total yield
4.25%
| Month | Balance | Interest to date |
|---|---|---|
| 1 | $10,034.74 | $34.74 |
| 2 | $10,069.61 | $69.61 |
| 3 | $10,104.60 | $104.60 |
| 4 | $10,139.71 | $139.71 |
| 5 | $10,174.94 | $174.94 |
| 6 | $10,210.29 | $210.29 |
| 7 | $10,245.76 | $245.76 |
| 8 | $10,281.36 | $281.36 |
| 9 | $10,317.09 | $317.09 |
| 10 | $10,352.93 | $352.93 |
| 11 | $10,388.90 | $388.90 |
| 12 | $10,425.00 | $425.00 |
What is the CD Calculator?
A CD calculator works out what a certificate of deposit will be worth at maturity. A CD is a time deposit: you commit a lump sum for a fixed term and the bank pays a fixed rate in exchange for knowing the money will stay put. Because both the rate and the term are contractual, the maturity value is known on the day you open it — one of the few genuinely predictable numbers in personal finance.
How the calculation works
You enter the deposit, the APY the institution is offering, and the term in months. The calculator converts the APY to its monthly equivalent and compounds the deposit forward to the end of the term. There are no ongoing contributions — that is what distinguishes a CD from a savings account — so the entire growth comes from the original deposit compounding untouched. The output shows the value at maturity, the interest earned, and the total yield as a percentage of what you put in.
The formula
Maturity value = P(1 + i)^n, where P is the deposit, i the monthly rate derived from the APY as (1 + APY)^(1/12) − 1, and n the term in months. Interest earned is simply the maturity value minus P. Total yield is that interest divided by P, expressed as a percentage — for a one-year CD it lands very close to the APY itself, which is a useful sanity check on any CD calculation.
Worked example
A $10,000 deposit at a 4.25% APY for 12 months matures at about $10,425, meaning roughly $425 in interest and a total yield near 4.25% — matching the APY, as it should over exactly one year. Extending the same deposit to a 60-month term at the same rate produces close to $12,300, because five years of compounding turns a single-year 4.25% into a cumulative gain above 23%.
Tips
- Compare CDs on APY and term together — a higher rate on a longer lock is not automatically better.
- Check the early withdrawal penalty before committing; it is usually several months of interest.
- Consider a CD ladder, splitting the money across staggered terms so part matures regularly.
- Confirm whether the CD renews automatically at maturity and what rate it would roll into.
- Keep your emergency fund out of CDs — the penalty defeats the purpose of liquid savings.
Common mistakes
- Locking money you may need and losing months of interest to the early withdrawal penalty.
- Letting a CD auto-renew into a much worse rate because the maturity date passed unnoticed.
- Assuming a longer term always pays more, which is untrue when the yield curve is inverted.
- Comparing a CD's total yield against a savings account's annual APY without matching the periods.
- Overlooking that CD interest is taxed as it is earned, not only when the CD matures.
Limitations
The calculation assumes the deposit is held untouched to maturity at the stated APY, with no early withdrawal, no additional deposits, and no automatic renewal into a different rate. It reports nominal dollars, so it does not adjust for inflation, and it excludes tax on the interest — which for most CDs is taxable annually as it accrues, even before you receive it.
Frequently asked questions
What is a certificate of deposit?
A CD is a deposit account holding a fixed sum for a fixed term at a fixed rate. In exchange for giving up access to the money, you generally receive a higher rate than an ordinary savings account pays.
What happens if I withdraw early?
Most CDs charge an early withdrawal penalty, commonly a set number of months of interest — often three to six months on shorter terms and up to a year on longer ones. The penalty can exceed the interest earned if you withdraw very early.
Is a CD insured?
CDs at FDIC-insured banks and NCUA-insured credit unions carry the same deposit protection as other accounts, up to the applicable limit per depositor, per institution, per ownership category.
How is CD interest taxed?
CD interest is generally taxable in the year it is credited, even on a multi-year CD where you do not receive the money until maturity. The institution reports it on Form 1099-INT.
What is a CD ladder?
A ladder splits your money across CDs with staggered maturities — say one, two, and three years — so a portion becomes available each year. It blends the higher rates of longer terms with regular access to part of the money.
Does a longer term always pay more?
Usually, but not always. When short-term rates exceed long-term ones, a one-year CD can out-yield a five-year one. Compare the actual offers rather than assuming the curve slopes upward.
What happens at maturity?
Many CDs renew automatically into a new term at the prevailing rate unless you act within a short grace period. That renewal rate is often uncompetitive, so it pays to diarise the maturity date.
CD or high-yield savings?
A CD locks the rate but also the money; high-yield savings stays liquid but the rate can fall at any time. In a falling-rate environment a CD protects your yield; if you might need the cash, savings is the safer structure.
Can I add money to an existing CD?
Standard CDs do not accept additional deposits after opening — that is why this calculator models a single lump sum. Some institutions offer add-on CDs, but they are the exception rather than the rule.
What is a bump-up or no-penalty CD?
A bump-up CD lets you move to a higher rate once if rates rise; a no-penalty CD allows early withdrawal without a charge. Both trade a slightly lower headline rate for that flexibility.
Related calculators
Related guides
Sources
- FDIC — Deposit Insurance
- Federal Reserve — H.15 Selected Interest Rates
- Investor.gov (SEC) — Compound Interest Calculator
How this page is produced and reviewed
Editorial process. Content is written by the CentCompass Research Team, then checked against the official publications listed above by Editorial Review before it goes live. This page was last reviewed on . See our editorial policy.
How the calculations work. Every result comes from a small, unit-tested calculation engine rather than a spreadsheet or a hardcoded table. Loans use the standard amortization formula, growth uses compound-interest math, income tax applies the federal progressive brackets, and payroll applies Social Security and Medicare rules. Our methodology sets out each one.
Where the figures come from. Tax brackets, standard deductions, FICA parameters, and contribution limits are stored once in a dated registry and read directly by the calculators — the same values appear in the text above, so the two can never drift apart. Each figure records its source, effective tax year, and review status on our data sources page.
Update policy. Regulatory figures are reviewed when the IRS, SSA, or another authority publishes new values — typically each autumn for the following tax year — and again at the scheduled review date recorded for each dataset. Figures awaiting a second reviewer are marked as draft on the data sources page until that check is complete.
Educational purposes only — not financial, tax, or investment advice (disclaimer).