Number CD Calculator
A CD quotes APY, and APY already includes compounding — which makes the maturity figure easy to check and easy to get wrong. Enter the deposit, APY and term and see the exact maturity value, the interest, and the balance at every year-end.
Year by year
| Year | Balance | Interest so far |
|---|---|---|
| Run the numbers to see the growth table. | ||
How it works
APY is the effective annual yield, so the maturity value is simply deposit × (1 + APY)years — the same at every compounding frequency, because APY already contains the compounding. The frequency still matters behind the scenes: from the APY this tool derives the nominal rate for that frequency (the rate the bank actually applies each period), which is how the year-by-year balances are built. Comparing two CDs? Compare APYs — the frequency is already inside them.
Formula & worked example
Formula: APY is the effective annual yield, so maturity value = deposit × (1 + APY)years — identical at every compounding frequency, because APY already contains the compounding. Behind the scenes the nominal rate for a frequency f is derived as f × ((1 + APY)1/f − 1) — at 5% APY compounded monthly, that nominal rate is 4.8889%.
Worked example: Deposit $10,000 at 5% APY for 3 years: year 1 ends at $10,500.00, year 2 at $11,025.00, and maturity pays $11,576.25 — $1,576.25 of interest, the same whether the bank compounds daily, monthly or annually.
When to use this
- You have money parked for a known date — a house deposit, tuition, a car — and want a return locked in today instead of a savings rate that can drift down.
- You are building a CD ladder and need the maturity value of each rung before you split the deposit up.
- A bank quotes an APY and you want to check that its printed maturity figure actually follows from it.
- You are deciding whether locking money away for five years pays enough over a one-year term to be worth losing access.
How to use it, step by step
- Enter the deposit you will genuinely leave untouched until maturity.
- Enter the APY exactly as quoted — not the nominal interest rate, which is a smaller number.
- Set the term in years; use a fraction for short CDs, so 18 months is 1.5.
- Pick the compounding frequency to see the nominal rate the bank applies each period.
- Read the maturity value and the year-by-year table, then re-run at the next term up to price the lock-in.
What the inputs mean
| Input | What it is | Typical values |
|---|---|---|
| Deposit | The lump sum you open the CD with and leave alone | From $500 starter CDs to $100,000+ jumbo deposits |
| APY | The effective annual yield the bank must quote | Competitive CDs have recently sat around 4–5% |
| Term (years) | How long the money is locked | 3 months to 5 years; 1 and 5 are the common rungs |
| Compounding | How often interest is credited behind the scenes | Daily or monthly at most banks |
Another worked example
Put $25,000 into a 5-year CD at 4.50% APY, compounded monthly: the nominal rate behind that APY is 4.41%, and the year-end balances run $26,125.00, $27,300.63, $28,529.15 and $29,812.97, reaching $31,154.55 at maturity — $6,154.55 of interest. Switch the compounding to daily and maturity is still $31,154.55, because both versions quote the same APY.
Frequently asked questions
How much is a $10,000 CD at 5% APY worth in 3 years?
$11,576.25 — $1,576.25 of interest. Because APY already includes compounding, the figure is the same whether the bank compounds daily, monthly or annually.
What is the difference between APY and the interest rate?
The rate is what is applied each period; the APY is what you effectively earn over a year after compounding. A 4.89% nominal rate compounded monthly is a 5.00% APY. Banks must quote APY on deposit products precisely so this comparison is fair.
Does compounding frequency change what I earn?
At the same APY, no — that is the point of APY. At the same nominal rate, yes: more frequent compounding earns slightly more. Always compare CDs by APY and term together.
What happens if I withdraw early?
Typically a penalty of 3–12 months of interest, which can eat into principal on short terms. The maturity value here assumes you hold to term — which is the entire deal a CD offers: a higher yield in exchange for leaving the money alone.
📈 What does inflation do to that CD?
A 5% yield against 3% inflation is a 2% real return. The Inflation Calculator shows what your maturity value will actually buy.
Can I add money to a CD after opening it?
Usually not. Most CDs accept only the opening deposit; extra money has to wait for maturity or go into a separate CD. At maturity there is typically a short grace window — often about a week — when you can add funds, withdraw, or renew before the CD rolls over automatically.
What is a CD ladder, and why build one?
A ladder splits a deposit across several terms, say 1, 2, 3, 4 and 5 years, so one CD matures every year. You give up a little of the longest term's yield in exchange for regular access to part of the money and regular chances to re-lock at whatever rates are doing then — a hedge against both rising and falling rates.