Editorial Policy

Standards & Frameworks

All calculators on CDCalculators.org are built on widely recognized US retail deposit math—not proprietary or opaque formulas. Our editorial and engineering standards align with frameworks referenced by the Federal Reserve, the FDIC, and major US banking institutions.

Calculation Methodology

• APY-based maturity balance. Final balance uses Principal × (1 + APY)^Years, consistent with how US banks advertise Certificate of Deposit yields under the Truth in Savings Act (Regulation DD).
• Annual Percentage Yield (APY). We treat APY as the all-in advertised rate that already reflects compounding—the same convention used in Federal Reserve and FFIEC disclosure guidance for deposit accounts.
• Compounding frequency. For growth charts and intermediate balances, we derive per-period rates from APY using standard periodic compounding (daily, monthly, quarterly, or annual)—so visualizations match the maturity APY outcome.
• Early withdrawal penalty (EWP). Penalty estimates follow the common industry approximation: (Total Interest ÷ Total Months) × Penalty Months. Actual EWP rules vary by institution and account terms.
• CD ladder strategies. Ladder rungs use equal principal splits across standard term buckets—a widely documented retail savings approach for liquidity and rate diversification.

Review & Updates

Core logic is open source and available for public review on GitHub. We update formulas when US regulatory definitions or industry conventions change materially.

Contact

Questions about our editorial standards? Visit our About Us page for contact details.