CD Calculator

A certificate of deposit (CD) locks in your money for a set term while paying a fixed rate, making it one of the simplest low-risk savings vehicles. This calculator lets you test deposit amounts, annual percentage yield (APY), and term length so you can see how much interest you might earn. The result panel stays open even before you enter numbers, so you always know where to look. Choose your currency first, then enter your deposit, the APY your bank quotes, the term in months, and how often interest compounds. Because APY already folds in compounding, this tool also shows an “APY check” derived from the nominal rate plus compounding so you can spot inconsistencies in marketing disclosures.

Inputs are straightforward. Deposit is the amount you place into the CD at the start; CDs generally do not allow additional contributions during the term. APY is the annual percentage yield the bank advertises. Term is the length of the CD in months. Compounding frequency controls how often interest is added to the balance: monthly, quarterly, semi-annually, or annually. The calculator converts APY back to an effective periodic rate to estimate the final maturity value. If you prefer to work from a nominal rate instead of APY, you can enter a nominal rate and see the implied APY, but most banks lead with APY so that is the primary field here.

How the math works: APY is defined as (1 + r/n)^(n) - 1, where r is the nominal annual rate and n is the number of compounding periods per year. To estimate maturity value from APY, the calculator uses M = P * (1 + APY)^(term/12). If you toggle compounding, it will also show a nominal-equivalent rate using r = n * ((1 + APY)^(1/n) - 1). The goal is to keep outputs transparent so you can compare offers across banks that might list slightly different details.

Penalty considerations: breaking a CD early often forfeits some interest. This calculator does not model penalties; it assumes you hold the CD to maturity. If you might need the funds sooner, model a shorter term or compare to a high-yield savings account. Also note that promotional “step-up” or “bump-up” CDs change rate mid-term; this fixed-rate model will not capture those features. Still, a quick baseline helps you judge whether a promo rate meaningfully improves your outcome versus a standard fixed CD.

Taxes: interest on CDs is generally taxable in the year it is paid or credited, even if you leave it in the bank. This calculator reports gross interest only—it does not account for taxes. If you hold CDs inside a tax-advantaged account (such as certain retirement accounts), the timing of tax may differ. Always check with a tax professional for your situation.

Liquidity: CDs trade liquidity for rate. If you are comparing a CD to a money market or savings account, think about your emergency fund size and whether locking funds could force you to borrow elsewhere at higher rates if an expense arises. A quick rule of thumb is to keep emergency funds liquid and use CDs for surplus cash you can truly set aside for the chosen term.

Laddering strategy: many savers split funds across multiple CDs with staggered maturities (a “ladder”) to improve average yield while keeping some liquidity. You can approximate ladder outcomes by running several CD calculations with different terms and amounts, then averaging the maturity outcomes according to your ladder plan. Keeping the result panel open makes it easy to jot down results and compare in a single view.

Action steps: pick currency, plug in deposit, APY, term, and compounding. Review maturity value and total interest. If you need flexibility, try shorter terms; if you want more yield, test longer terms and compare the interest gain versus the loss of liquidity. Revisit offers regularly—rates change with market conditions and bank promotions.