CD calculator, balance, APY and ladder.

A CD calculator, or certificate of deposit calculator, works out how much a CD pays by the end of its term. You give it the deposit, the rate and the term. It gives back the ending balance and the interest earned. This one also handles the three things that the simple versions skip: a rate typed as APY or as a nominal rate, extra money added each time the CD renews, and a ladder that spreads money over several terms. It also lets you test an early withdrawal penalty. It claims no rate and names no bank. Every rate in a box is an example, so type the one you were offered.

How to use the CD calculator

1. Under One CD, type the Deposit, such as 10,000.
2. Type the Rate (%) and choose whether it is an APY or a Nominal rate under The rate is. Banks usually print the APY.
3. Choose how often Interest is added: daily, monthly, quarterly, twice a year or yearly.
4. Type the Term in months or years.
5. Read the ending balance, the interest earned and the table. Copy result copies a short summary, Download table (CSV) saves the table, and Copy link to these numbers gives a link that opens with the same inputs.

APY and the nominal rate

The nominal rate is the stated yearly rate before compounding. The APY, the annual percentage yield, is what you really earn over a year once the interest itself starts earning interest. The two are linked by one formula: APY = (1 + r / n)ⁿ − 1, where r is the nominal rate and n is how many times a year interest is added. Turned round, r = n × ((1 + APY)^1/n − 1).

Take a 4% APY with monthly compounding. The nominal rate is 12 × (1.04^1/12 − 1), which is 3.9285%. Now take a 4% nominal rate instead. Added monthly, it gives an APY of 4.0742%, so 10,000 grows to 10,407.42 in a year. Added daily on a 365 day year, the same 4% gives an APY of 4.0808% and 10,408.08. Added quarterly it gives 4.0604%. The more often interest is added, the higher the APY for the same nominal rate. When you type an APY, the compounding choice changes only the nominal rate shown, not the ending balance.

Worked examples

The last row shows how a part period is treated. With yearly compounding, the first year adds 4% to give 10,400. The next six months earn simple interest, half of a year at 4%, which is 10,400 × 0.02 = 208, so the balance is 10,608. Each full period is compounded and the leftover part of a period earns simple interest.

Renewals and extra deposits

Open Renewals and extra deposits to roll the CD over. Type how many times it renews and how much you add each time. You can also type a new rate that applies after the first term, or leave the box empty to keep the same one. For example, 10,000 at 4% APY for 12 months, renewed twice with 1,000 added each time at the same rate, goes to 10,400, then 11,400 grows to 11,856, then 12,856 grows to 13,370.24. You put in 12,000 and earned 1,370.24.

Early withdrawal penalty

Many CDs charge a penalty if you take the money out early, often counted as a number of months of interest. The rule differs by bank and by term, so this page assumes nothing: you type the number of months. Open Early withdrawal, type the months of penalty and the month you would withdraw. The page uses penalty = months × (nominal rate ÷ 12) × balance. With the 4% APY example, a 3 month penalty and a withdrawal in month 6, the balance is 10,198.04, the penalty is 100.16 and you receive 10,097.88. The penalty is covered by the interest from month 4 on. Withdraw in month 3 and you get 9,999.35, which is slightly less than you put in. Your contract may count the penalty on a different amount, so check it.

Ladders

A CD ladder splits money across CDs with different terms, so some of it comes back sooner while the rest earns a longer-term rate. Switch to Ladder and type one rung per line as months, rate and an optional amount. The default example puts 2,500 in each of four rungs: 6 months at 3% APY, 12 months at 3.5%, 24 months at 4% and 36 months at 4.5%. They pay out 2,537.22, 2,587.50, 2,704.00 and 2,852.92, a total of 10,681.64 and 681.64 of interest. The first money is back after 6 months and the last after 36. These rates are made up for the example.

Why a bank’s figure may differ

• Some banks count interest on the exact days of the term, or on a 360 day year.
• Interest on a CD is usually taxable, and the page does not take tax off.
• Rates can be different for renewals, and many banks renew a CD into whatever rate they offer at that time.

To see how regular deposits grow, use the compound interest calculator. To see what the final balance would buy, try the inflation calculator. For the other side of interest, where you pay it, there is the loan calculator.