CD calculator
A certificate of deposit locks money for a set term at a fixed rate. Enter the deposit, the rate, the term in months and how often interest compounds. You get the balance at maturity, the interest earned and the effective annual yield.
Runs in your browser: nothing you enter is sent anywhere.
How to use it
- Enter the deposit, the stated rate and the term in months.
- Pick how often the bank compounds interest.
- Optionally enter a tax rate on interest.
How it works
- Years = months ÷ 12.
- Balance = deposit × (1 + rate ÷ n)^(n × years), with n = 1, 4, 12 or 365.
- APY = (1 + rate ÷ n)^n − 1.
- Tax = tax rate × interest; interest after tax = interest − tax.
Worked example
Deposit 10,000 at 5% for 12 months. Compounded annually the balance is 10,500.00. Compounded monthly, 1.0041667^12 = 1.0511619, so the balance is 10,511.62, the interest is 511.62 and the APY is 5.1162%.
Tips
- Compare CDs by APY, not by the stated rate alone.
- Check whether the bank pays interest out or adds it to the CD; this tool assumes it is added.
- Terms and penalties vary by bank.
Frequently asked questions
How is the CD balance calculated?
Balance = deposit × (1 + rate ÷ n)^(n × years), where n is the number of compounding periods a year. 10,000 at 5% compounded monthly for 12 months grows to 10,511.62.
What is the difference between the rate and the APY?
The rate is the stated yearly rate. The APY includes compounding within the year: (1 + rate ÷ n)^n − 1. At 5% compounded monthly the APY is about 5.1162%.
Does the compounding frequency matter much?
A little. At 5% for one year, annual compounding gives 500 of interest on 10,000, monthly gives 511.62 and quarterly gives 509.45. Banks state their own method, so check your CD terms.
Does the tax field use a real tax rule?
No. It simply takes the percentage you enter off the interest. Use the rate that applies to you, or leave it at 0.
Are early withdrawal penalties included?
No. The result assumes you keep the CD until maturity and the rate stays fixed.