How does the CD calculator work?
Enter your deposit, the CD's APY, the term in months, your tax bracket and an inflation estimate. The tool grows your balance at the stated APY, then shows a second figure after subtracting tax on the interest each year, and a third figure that discounts the after-tax balance for inflation so you can see what the money is really worth in today's dollars.
How much does a CD really earn you?
A certificate of deposit advertises one number, its rate, but two other forces quietly chip away at what you actually keep: taxes and inflation. Say you put $20,000 into a CD paying 4.5%, compounded annually, for five years. Before anything else is subtracted, that grows to a little over $24,900, about $4,900 in interest. Once you account for a 22% tax bracket and a modest inflation estimate, the real gain you walk away with, measured in today's purchasing power, is a good deal smaller than the headline rate suggests. The calculator below runs those numbers for your own deposit, rate and term.
How to use the CD calculator
- Enter your deposit. This is the amount you are placing into the CD, for example $10,000 or $75,000.
- Enter the APY. Use the annual percentage yield the bank quotes, which already reflects how often the CD compounds.
- Set the term in months. CDs are usually quoted in months rather than years, so a 5-year CD would be entered as 60 months.
- Add your tax bracket. Enter your marginal federal tax rate so the calculator can show the after-tax balance, since CD interest is taxed as it is earned.
- Add an inflation estimate. Enter a reasonable annual inflation rate to see what your after-tax balance is worth once rising prices are factored in.
What the calculator is actually showing you
A CD is a fixed-term deposit account: you hand a bank a lump sum, agree not to touch it for a set period, and the bank pays a guaranteed yield in return. Pull the money out before the term ends and most banks charge a penalty, usually a set number of months of interest.
This tool runs three layers of math on top of that simple idea. First, it grows your deposit at the APY you entered for the number of months in your term. Second, because CD interest is taxable every year it accrues, whether or not you touch it, it applies your tax bracket to that growth so you can see the after-tax figure. Third, it takes that after-tax balance and discounts it by your inflation estimate, which shows the balance in terms of what it can actually buy rather than the raw dollar figure. When inflation runs hotter than your after-tax yield, that final number can shrink even as your account statement keeps showing growth.
The upshot: a CD quoted at 4.5% rarely nets you anything close to 4.5% in real terms. Once a 22% tax bracket and 3% inflation are layered on, the same CD often lands closer to a real return of well under 1%.
Why the yearly tax bill matters so much
This is the single biggest difference between a bank CD and a multi-year guaranteed annuity. A CD's interest is taxed the year it is credited, full stop, even if the money sits untouched inside the account until maturity. Paying the IRS every year means less of your balance is left to keep compounding, which slows your growth compared to a product where nothing is taxed until you withdraw.
A MYGA works the opposite way. Interest builds up without a tax bill along the way, so the entire balance, including money that would otherwise have gone to taxes, stays invested and keeps growing. Run both side by side in the CD vs annuity calculator, or isolate the pure effect of compounding with the compound interest calculator.
CDs carry FDIC protection up to $250,000 per depositor, per bank, which is a large part of their appeal for money you cannot afford to lose. Details on that coverage are on the FDIC's deposit insurance page.
A quick example. Diane, 63, has $60,000 sitting in savings and wants somewhere safe to park it for four years before she needs it. Her bank offers a 4-year CD at a 4.7% APY. She plugs in $60,000, 4.7%, a 48-month term and her 24% tax bracket. The pretax balance climbs to roughly $71,800, about $11,800 of interest, but after her 24% tax bite on that interest, she keeps closer to $8,970 of it. Layering in a 3% inflation assumption shows her that a meaningful slice of even the after-tax gain is being eaten by rising prices, which nudges her to compare a same-term MYGA before she renews.
CD vs MYGA at a glance
| Feature | Bank CD | MYGA (fixed annuity) |
|---|---|---|
| Taxed | Every year, as it accrues | Deferred until you withdraw |
| Backed by | FDIC, up to $250,000 | Insurance carrier plus your state guaranty association |
| Common term | A few months up to 5 years | 2 to 10 years |
| Early withdrawal | Flat interest penalty | Surrender charge, usually with a free-withdrawal allowance |
| Fits best | Cash you may need soon | Money you can leave alone for retirement |
Rates on both products move constantly, so check current numbers on our MYGA rate guide or browse the full annuity calculators before deciding.
Frequently asked questions
How is CD interest taxed?
The bank reports your CD interest as taxable income for the year it is credited to your account, even if the CD has not matured yet and you never touched the cash. You will see it on a 1099-INT at tax time. A CD held inside an IRA is the exception, since it grows without a tax bill until you take money out of the IRA itself.
What does APY actually mean?
APY, or annual percentage yield, is the rate a CD actually pays over a full year once compounding is factored in. A CD that compounds more often, say daily instead of annually, will show a slightly higher APY than one with an identical stated rate that only compounds once a year. Comparing APYs, not stated rates, is the fair way to shop between two CDs.
Does a CD keep up with inflation?
Not automatically. A CD locks in a fixed rate for its term, so if prices rise faster than that rate, the buying power of your balance shrinks even while the dollar amount on your statement keeps growing. This calculator's inflation-adjusted figure shows that gap directly. A CD is excellent at protecting your principal from loss, but it makes no promise about keeping pace with the cost of living.
Should I choose a CD or a MYGA?
It comes down to when you need the money and what tax bracket you are in. A CD is simple, FDIC-insured and fully accessible the moment it matures, which fits money you may need soon. A multi-year guaranteed annuity typically offers a comparable or better rate plus tax deferral, which tends to leave more money in your pocket over several years if you can leave it alone. For cash earmarked well past your CD's term, run both through the calculator and compare.
What happens at the end of a CD's term?
Most banks give you a short window, often about 10 days, to decide what to do with a maturing CD. You can withdraw everything, roll it into a new CD, or move the funds elsewhere. Do nothing and many banks will automatically renew you into a new CD at whatever rate is current then, which is sometimes lower than what you were earning. Put the maturity date on your calendar so the renewal happens on your terms.
Sources
Educational only, not investment, tax or legal advice. Tax Free Wealth Plan LLC is a licensed insurance agency, not a registered investment adviser or broker-dealer. Annuities are not bank deposits, are not FDIC insured and are not guaranteed by any government agency. Guarantees are backed solely by the claims-paying ability of the issuing insurance company. Features, rates and availability vary by state and change over time; the contract and disclosure documents govern.