APY already includes compounding
A CD is quoted by its APY — the annual percentage yield — which is the effective annual return after compounding. That’s why the maturity value depends only on the APY and the term, not on whether the bank credits interest daily, monthly, or once a year. The compounding frequency only changes the size of each periodic credit; the yearly total is identical.
The maturity formula
Value = Deposit · (1 + APY)months ÷ 12
The periodic rate shown in the result is solved back out of the APY as (1 + APY)1 ÷ periods − 1, so the schedule view always agrees with the headline figure.
What makes this calculator different
- It models the early-withdrawal penalty. Most CD calculators stop at the maturity value. We show what you’d actually keep if you break the CD early — the value at that point, minus a penalty of several months’ interest.
- It warns when the penalty eats your principal. Withdraw early enough and the penalty can exceed the interest you’ve earned, leaving you with less than you deposited. We flag that case explicitly.
- It makes the APY math clear. Change the compounding frequency and watch the maturity value stay put — because APY already bakes compounding in.
- Shareable and visual. A growth chart plus a copyable link so you can compare scenarios or save one for later.
Frequently asked questions
What’s the difference between APY and interest rate?+
The interest rate is the nominal rate before compounding. APY (annual percentage yield) is the effective rate after compounding is applied, so it’s always equal to or higher than the nominal rate. Because APY already bakes in compounding, a CD quoted at a given APY earns the same amount at maturity whether the bank compounds daily, monthly, or annually — the compounding frequency only changes the size of each periodic credit, not the yearly total. APY is the apples-to-apples number to compare CDs on, which is why this calculator works directly from it.
How does an early-withdrawal penalty work?+
If you take your money out of a CD before its maturity date, the bank charges a penalty — typically a set number of months of interest (often 3 months on short CDs and 6–12 months on longer ones). The penalty is calculated on your deposit, not on what you’ve earned, so if you withdraw early in the term the penalty can exceed the interest you’ve accrued and dip into your original principal. This calculator models that exact scenario and flags when you’d walk away with less than you put in.
What is a CD ladder?+
A CD ladder splits your money across several CDs with staggered maturity dates — for example, equal amounts in 1-, 2-, 3-, 4-, and 5-year CDs. As each rung matures you reinvest it into a new long-term CD. This gives you regular access to a portion of your cash (reducing the chance you’ll ever need to break a CD and pay a penalty) while still capturing the higher rates that longer terms usually pay.
Are CDs safe? Are they FDIC insured?+
CDs from FDIC-insured banks (or NCUA-insured credit unions) are insured up to $250,000 per depositor, per institution, per ownership category. That makes them one of the lowest-risk places to hold cash — your principal and accrued interest are protected even if the bank fails. The main risks are not credit risk but opportunity cost: your money is locked up for the term, and an early-withdrawal penalty applies if you need it sooner.
CD vs high-yield savings — which is better?+
A CD locks your rate for a fixed term, which is great when rates are falling but means you can’t access the money without a penalty. A high-yield savings account pays a variable rate that can rise or fall, but lets you withdraw any time. Use a CD for money you won’t need until a known date and want a guaranteed return on; use high-yield savings for an emergency fund or cash you may need on short notice. Many savers use both.
Disclaimer: This calculator is for educational purposes only. Actual CD rates, compounding conventions, and early-withdrawal penalties vary by institution and product, and some penalties are calculated differently than the months-of-interest model used here. It is not financial advice.