CD Interest Calculator
This CD interest and CD rate calculator models a fixed-rate certificate of deposit from the convention the institution actually quotes. Enter APY as an effective annual yield, or enter a nominal annual rate with its compounding frequency, then compare maturity value and term yield. The same compound-interest model can estimate a fixed deposit (FD) or a U.S. certificate of deposit. Whether a “good FD” is suitable depends on term, rate, access, tax, insurance, and penalty rules outside this calculation.
How to use the CD Interest Calculator
Enter opening principal, annual rate, whether the rate is APY or nominal, term in months, and compounding frequency when nominal.
Review whether the bank quotes APY or APR, the exact maturity date, compounding terms, insurance limits, taxes, and penalty rules.
Read estimated maturity balance, interest earned, effective term yield, and effective annual yield.
Formula
For APY y, maturity value A = P × (1+y)^(months/12). For nominal rate r compounded n times yearly, first convert to APY = (1+r/n)^n − 1, then apply the same term formula.
Example
A $10,000 CD quoting 4.50% APY for 12 months grows to $10,450; a 4.50% nominal rate compounded monthly grows to about $10,459.40.
Assumptions and limitations
- The calculation assumes a fixed rate, no interim additions or withdrawals, and reinvestment through maturity; penalties, taxes, and institution-specific day counts are excluded.
- CD Interest Calculator treats the entered values as estimates and does not infer missing project, account, or personal details.
- Calculations retain working precision except where the cited method requires an intermediate rounding step; displayed values are then formatted separately. Source rules and dated rates must be rechecked when they change.
Sources
- Federal Deposit Insurance Corporation: Shopping for a Certificate of Deposit?CD terms, maturity, early-withdrawal penalties, and deposit-insurance context. Reviewed 2026-08-14.
- U.S. Securities and Exchange Commission: Compound Interest CalculatorCompound-growth inputs and future-value concepts. Reviewed 2026-08-14.
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Frequently asked questions
How does the CD Interest Calculator work?
For APY y, maturity value A = P × (1+y)^(months/12). For nominal rate r compounded n times yearly, first convert to APY = (1+r/n)^n − 1, then apply the same term formula.
What information should I enter in the CD Interest Calculator?
Enter opening principal, annual rate, whether the rate is APY or nominal, term in months, and compounding frequency when nominal, then verify whether the bank quotes APY or APR, the exact maturity date, compounding terms, insurance limits, taxes, and penalty rules.
What should I verify before using this CD Interest Calculator result?
The calculation assumes a fixed rate, no interim additions or withdrawals, and reinvestment through maturity; penalties, taxes, and institution-specific day counts are excluded.
Reviewed 2026-08-14 · apy-or-nominal-deposit-v2 · content-2026-08-14 · Trusty Calculator Editorial Team