CD Calculator: Calculate Certificate of Deposit Interest & Maturity Value

What Is a CD Calculator?

A CD calculator is a certificate of deposit calculator that tells you, before you commit a single dollar, exactly what a CD will be worth on the day it matures. You enter three things your deposit, the term length and the rate and the tool returns your total balance, the interest earned and a year-by-year growth chart of how the money compounds.

The reason this works so cleanly is what makes CDs unusual in the first place. A certificate of deposit is a time deposit: you hand a bank or credit union a fixed sum for a fixed period, and in exchange you get a fixed rate that’s locked for the entire term. Nothing floats, nothing fluctuates, and deposits are federally insured up to $250,000 per depositor (FDIC at banks, NCUA at credit unions). Because every variable is fixed, your payout is knowable to the cent in advance and that’s precisely what this free CD calculator gives you.

That certainty is also why savers use CDs for money with a date attached: a wedding two years out, a car down payment next spring, or a slice of an emergency cushion you’re sure you won’t touch. Run the numbers first, and the “should I lock this up?” decision gets a lot easier.

How to Calculate CD Interest (The CD Formula)

Underneath every CD interest calculator is the standard compound interest formula:

• A the ending balance at maturity
• P your principal (the initial deposit)
• r the annual interest rate as a decimal
• n how many times interest compounds per year (365 daily, 12 monthly, 4 quarterly)
• t the term in years

Your interest is simply A − P. And if the rate you have is already an APY, the math collapses into an even simpler shortcut, because APY has compounding baked in:

Worked example: put $10,000 into a 3-year CD at 4.00% APY and you get 10,000 × 1.04³ = $11,248.64 that’s $1,248.64 of interest for doing nothing but waiting. The calculator above runs this exact math, then goes further with taxes, a national-average comparison and a full schedule.

APY vs APR: Which Rate Goes in a CD Calculator?

This is the mistake that quietly breaks most homemade spreadsheets. APY (annual percentage yield) is your true yearly return with compounding already included it’s the big number banks advertise. APR (the nominal annual rate) is the raw rate before compounding. A 4.00% APR compounded daily actually works out to about a 4.08% APY.

Feed an APY into the compound interest formula as if it were a nominal rate and you compound it twice, overstating your earnings. Feed an APR in without compounding and you understate them. That’s why this CD calculator asks which one you have: pick APY and it uses the shortcut formula; pick APR under Advanced options and it compounds at the frequency you choose, then shows the resulting effective APY so you can compare offers apples-to-apples.

CD Calculator Compounded Daily vs Monthly

Most large online banks compound CD interest daily and credit it to your balance monthly; plenty of community banks and credit unions compound monthly or quarterly instead. More frequent compounding earns slightly more: a 4.00% nominal rate becomes 4.081% APY compounded daily versus 4.074% compounded monthly. On $10,000 over a year, that’s under a dollar small, but real, and it grows with bigger deposits and longer terms.

The practical takeaway: if you’re comparing two CDs, compare their APYs and the compounding question disappears, because APY already accounts for it. Use the compounding dropdown here when all you’ve been quoted is a nominal rate, or when you’re curious how daily compounding stacks up against monthly.

How Much Will $10,000 Make in a 6-Month CD?

In a 6-month CD, $10,000 earns about $198 at 4.00% APY and about $222.52 at 4.50% APY. A 6-month CD collects roughly half the advertised annual yield, because your money only works for half a year.

Stretch the same deposit further and the picture changes fast: a 1-year CD at 4.00% APY pays a clean $400, a 3-year CD compounds to $1,248.64, and a 5-year CD reaches $2,166.53 more than five times the one-year payout, with the extra coming from compounding. Short 3-month CDs earn less in absolute terms (about $98.53 at 4.00% APY) but return your cash fast, which is why they’re popular parking spots between bigger decisions. The reference table above lays out the full grid; the calculator lets you test your own deposit, whether that’s $500 or $250,000.

CD Rates in 2026: Where They Stand

CD yields peaked above 5% in 2023–2024, then started sliding once the Federal Reserve began cutting rates in late 2024 a drift that continued through 2025’s cuts and into 2026. The strongest offers from online banks now cluster around the low-4% APY range, while the national average across all banks sits far lower that’s the gap the comparison line in the chart above makes visible. One quirk of this cycle: shorter terms often out-yield longer ones, so a top 6- or 12-month CD can pay more than a 5-year CD from the same bank.

Two things follow from that. First, don’t assume longer automatically means better run both terms through the calculator and compare the actual dollar outcomes. Second, if you find a competitive rate and you’re confident you won’t need the cash, locking it in protects you if rates keep drifting down. Big brick-and-mortar banks still pay near-zero on many CDs, so the spread between a lazy choice and a shopped one is often the biggest “rate” decision you’ll make.

CD Early Withdrawal Penalty: What Breaking a CD Costs

Break a CD before maturity and the bank claws back interest typically anywhere from three months’ worth on short CDs to a full year’s interest (or more) on long ones. On a $10,000 5-year CD at 4.00% APY, surrendering a year of interest means handing back roughly $400 of your earnings, and if you exit very early the penalty can even nibble into principal at some institutions.

Three ways to stay out of that trap: only lock up money you genuinely won’t need before the maturity date; consider a no-penalty CD if flexibility matters more than a slightly higher rate; or build a ladder (next section) so a rung is always close to maturing. And know the one exception where breaking a CD makes sense when rates have jumped so much that the new CD’s extra earnings outweigh the penalty. The calculator makes that comparison a two-minute job.

CD Ladder Strategy: Plan One With the Calculator

A CD ladder splits one lump sum across several terms instead of one. Rather than putting $12,000 into a single 3-year CD, you’d open three $4,000 CDs with 1-, 2- and 3-year terms. Every year a rung matures, handing you cash you can spend or roll into a new long-term CD at whatever rates look like then.

You get the best of both worlds: most of your money earns longer-term rates, but you’re never more than a year from access and you’re never fully locked into one moment’s rate environment. To plan a ladder here, run each rung through the calculator separately (same deposit, different terms) and jot down the maturity values. If rates are falling, ladders let you down gently; if they rise, your maturing rungs catch the better rates.

Do You Pay Taxes on CD Interest?

Yes CD interest is taxed as ordinary income in the year it’s credited to you, even if you never withdraw a cent until maturity. Your bank will send a 1099-INT for any year you earn $10 or more. So a saver in the 22% federal bracket who earns $400 of CD interest actually keeps about $312, before any state tax.

That’s why this tool includes a marginal tax rate field under Advanced options. Type your combined rate in and the breakdown panel shows after-tax earnings alongside the headline number, which is the figure that actually matters for comparing a CD against, say, paying down debt. One caveat worth knowing: CDs held inside an IRA grow tax-deferred (or tax-free in a Roth), so the tax field is for regular taxable accounts.

Types of CDs This Calculator Covers

• Traditional CD fixed rate, fixed term, penalty for early exit. The default, and usually the best rate.
• No-penalty CD withdraw the full balance after a short waiting period with no fee, in exchange for a slightly lower APY.
• Bump-up CD lets you raise your rate once if the bank’s rates climb mid-term.
• Jumbo CD requires a large deposit (often $100,000+) and sometimes pays a touch more for it.
• Brokered CD bought through a brokerage; interest typically doesn’t compound, so this calculator’s compounding math applies to bank and credit union CDs.

Whichever flavor you’re weighing, the decision comes down to the same three numbers deposit, term, rate and this simple CD calculator turns them into a dollar figure you can actually plan around.