Reference formulas and worked examples below keep their stated units. Monetary examples use USD; dimensional examples use US customary units unless labeled otherwise. Metric calculator inputs are converted to these reference units before calculation. Choosing another currency does not convert example amounts or exchange money.
How to use this cd calculator
Estimate a certificate of deposit balance at maturity from its APY, deposit amount, and term. See principal and modeled interest separately.
How the calculation works
Maturity balance = initial deposit × (1 + APY ÷ 100)^(months ÷ 12).
Interest = maturity balance − deposit. Do not divide the APY by 12 and compound again; that would change the effective yield.
Worked example
A $10,000 deposit at 4% APY for 12 months grows to $10,400, earning $400 under this model.
Limits and assumptions
Assumes the APY is fixed and earnings stay deposited. Actual products may accrue by exact dates. Taxes, fees, early-withdrawal penalties, and renewal terms are excluded.
Frequently asked questions
Should I enter APY or the stated interest rate?
Enter APY, which includes the effect of compounding.
Can I model a six-month CD?
Yes. Enter 6 months; the model applies half a year of effective growth.
Does this include early withdrawal?
No. It models holding the deposit to maturity.