CD Calculator
Calculate the maturity balance and total interest earned on a certificate of deposit (CD) given the deposit amount, APY, and term in months.
Calculator Inputs
Sets the currency this calculator's numbers are denominated in. This is presentation only — it does NOT convert your numbers between currencies, it only changes how they're formatted.
The amount deposited into the CD.
Annual Percentage Yield offered on the CD.
How long the CD is held before maturity.
- Maturity Balance
- $10,400.00
- Total Interest Earned
- $400.00
About these results
CalcSpectrum calculators produce automated estimates using established formulas and the specific values you enter. Because real-world outcomes depend on input accuracy, mathematical assumptions, and rounding conventions, please verify critical figures with an appropriately qualified financial, tax, medical, legal, or other professional, as relevant.
Financial Notice: These figures are informational estimates for personal planning only. They do not constitute financial, investment, tax, or legal advice, nor do they represent a lending offer or credit approval. Provider and financial institution figures, rates, fees, and underwriting requirements may differ.
How It's Calculated
Formula
A certificate of deposit (CD) pays a fixed Annual Percentage Yield (APY) in exchange for locking up your deposit for a set term. Because APY already reflects a full year of compounding by definition, this calculator applies it directly over the term expressed in years: Maturity Balance = Deposit × (1 + APY/100)^t, where t is the term in months divided by 12. Total interest earned is simply the maturity balance minus the original deposit. This calculator computes the standard hold-to-maturity outcome only — it does not model early-withdrawal penalties, since penalty terms (a certain number of months' interest, a flat fee, etc.) vary by financial institution and aren't a fixed mathematical rule. If you're considering withdrawing early, check your CD's specific penalty terms separately.
Worked Examples
Standard case: $10,000 deposit, 4% APY, 12-month term
- Term in years: t = 12 / 12 = 1
- Maturity balance: 10,000 × (1 + 0.04)^1 = $10,400.00
- Interest earned: 10,400 − 10,000 = $400.00
Multi-year term: $5,000 deposit, 5% APY, 24-month term
- Term in years: t = 24 / 12 = 2
- Maturity balance: 5,000 × (1.05)^2 = $5,512.50
- Interest earned: 5,512.50 − 5,000 = $512.50
Frequently Asked Questions
Does this calculator include early-withdrawal penalties?
No. Early-withdrawal penalty structures (a number of months' forfeited interest, a flat dollar fee, or some other formula) vary by institution and CD product, so there's no single fixed rule to apply. This calculator computes the standard outcome if the CD is held to full maturity — check your specific CD's terms for its early-withdrawal penalty.
Why does the formula use APY directly instead of a nominal interest rate?
APY (Annual Percentage Yield) is, by definition, already the effective annual return after accounting for compounding — that's exactly what distinguishes it from a nominal (stated) interest rate. Since CDs are almost always advertised by APY, applying it directly once per year (raised to the power of the term in years) gives the correct maturity value without needing to know an underlying compounding frequency.
What happens with a term shorter than 12 months?
The term is converted to a fraction of a year (e.g. 6 months = 0.5 years) and used as a fractional exponent in the same formula — a 6-month CD earns proportionally less than a full year at the same APY, following standard compound-growth math.
Can the APY be 0%?
Yes — 0% is a valid input. The maturity balance simply equals the original deposit with no interest earned, which is the expected boundary case.