CD Calculator
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Results
$10,000.00 in a CD for 18 months at 4.25% APY grows to $10,644.23, earning $644.23
| Month | Interest that month | Balance |
|---|---|---|
| 1 | $34.74 | $10,034.74 |
| 2 | $34.87 | $10,069.61 |
| 3 | $34.99 | $10,104.60 |
| 4 | $35.11 | $10,139.71 |
| 5 | $35.23 | $10,174.94 |
| 6 | $35.35 | $10,210.29 |
| 7 | $35.48 | $10,245.76 |
| 8 | $35.60 | $10,281.36 |
| 9 | $35.72 | $10,317.09 |
| 10 | $35.85 | $10,352.93 |
| 11 | $35.97 | $10,388.90 |
| 12 | $36.10 | $10,425.00 |
Taking money out before the CD matures usually means an early-withdrawal penalty, often a set number of months of interest. Check your CD’s terms.
How to use the CD calculator
- Enter the amount you will deposit and the term in months (a 2-year CD is 24 months).
- Choose how the bank quotes the CD. Most quote an APY. If you have an interest rate and a compounding schedule instead, choose that option.
- Optionally enter the tax rate you pay on interest to see what you keep.
- Read the value at maturity, the interest earned, the APY and the balance month by month.
CD formula
APY = (1 + r ÷ n)n − 1
So: Maturity value = D × (1 + r ÷ n)n × months ÷ 12
D is the deposit, r the nominal annual interest rate as a decimal and n how many times a year interest compounds (365 for daily). The APY (annual percentage yield) is the growth over a full year with compounding included. Because the APY already includes compounding, you don't need the compounding schedule when you have the APY: the two formulas give the same answer.
For terms that aren't whole years, the APY is applied for the fraction of the year. The monthly table spreads the compounding evenly across months; a bank that compounds daily credits slightly different amounts in 30-day and 31-day months, but the maturity value is the same.
Worked example
You put $10,000 in an 18-month CD with a 4.25% APY.
- Maturity value = $10,000 × 1.04251.5 = $10,644.23.
- Interest earned: $644.23.
- A CD quoted as 4.17% compounded daily has an APY of 4.258%, and the same deposit grows to $10,645.44. A slightly lower headline rate can match or beat a higher one once compounding is included, which is why the APY is the number to compare.
Interest on a $10,000 CD by APY and term
| APY | 6 months | 12 months | 24 months | 60 months |
|---|---|---|---|---|
| 3% | $148.89 | $300.00 | $609.00 | $1,592.74 |
| 3.5% | $173.49 | $350.00 | $712.25 | $1,876.86 |
| 4% | $198.04 | $400.00 | $816.00 | $2,166.53 |
| 4.5% | $222.52 | $450.00 | $920.25 | $2,461.82 |
| 5% | $246.95 | $500.00 | $1,025.00 | $2,762.82 |
The APYs are examples, not current offers. Over 12 months the interest is exactly APY × deposit. Over 60 months it is more than five times that, because each year's interest also earns interest.
CD ladders
A ladder splits your money across CDs that mature at different times, so part of it becomes available every year while the rest stays in longer, often higher-rate terms. For example, $25,000 split into five $5,000 CDs of 1 to 5 years, all at an assumed 4% APY, would mature at:
| CD term | Value at maturity |
|---|---|
| 1 year | $5,200.00 |
| 2 years | $5,408.00 |
| 3 years | $5,624.32 |
| 4 years | $5,849.29 |
| 5 years | $6,083.26 |
In practice longer CDs often pay a different rate from shorter ones, so enter each rung's own APY in the calculator.
Things to check before you open a CD
- Early-withdrawal penalty. Usually a number of months of interest. It can eat into the deposit itself if you withdraw very early.
- What happens at maturity. Many CDs renew automatically at whatever rate applies then, unless you act during the grace period.
- How interest is paid. If interest is paid out to another account rather than added to the CD, it does not compound; use the simple interest calculator instead.
- Tax. Interest is usually taxable in the year it is credited, even if you can't withdraw it yet. Compare a CD with a regular account in the savings calculator.
Frequently asked questions
How much interest will a $10,000 CD earn?
It depends on the APY and the term. At 4.25% APY, a $10,000 CD earns $425.00 in 12 months and $644.23 in 18 months, when it is worth $10,644.23.
What is the difference between a CD’s interest rate and its APY?
The interest rate is the nominal yearly rate; the APY includes compounding. A rate of 4.17% compounded daily is an APY of 4.258%. Compare CDs by APY, since it puts every compounding schedule on the same footing.
How do you calculate CD interest for a term that is not a whole year?
Raise 1 + APY to the power of the term in years. An 18-month CD at 4.25% APY grows by 1.0425^1.5 = 1.0644, so $10,000 becomes $10,644.23.
Is CD interest compounded?
Usually yes, often daily or monthly, as long as the interest stays in the CD. That is why 60 months at 4% APY earns $2,166.53 on $10,000 rather than 5 × $400 = $2,000. If interest is paid out instead, it does not compound.
What happens if I withdraw from a CD early?
Most banks charge an early-withdrawal penalty, commonly a set number of months of interest. The exact penalty is in the CD’s terms, and on a very early withdrawal it can reduce the amount you deposited.