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CD Compound Interest Calculator

Compounding frequency is the hidden variable that separates competitive bank Certificates of Deposit from standard accounts. This CD Compound Interest

Finance
$
Principal deposit into the Certificate of Deposit
% APR
Stated nominal interest rate before compounding frequency is applied
years
Holding period in years
Formula & Methodology
FV = Deposit × (1 + r ÷ n)^(n × t) | APY = [(1 + r ÷ n)^n] − 1

When a CD compounds more frequently (e.g. daily n=365 vs annual n=1), interest generated each day is added to the principal and earns subsequent interest immediately. This compounding acceleration produces a higher effective yield (APY) from the identical stated nominal APR.

Maturity Value with Daily Compounding (5.1267% APY)

$11,618.22 Daily Compounding

Overview

Compounding frequency is the hidden variable that separates competitive bank Certificates of Deposit from standard accounts. This CD Compound Interest Calculator evaluates a single deposit and stated nominal APR across five distinct compounding frequencies—daily, monthly, quarterly, semi-annually, and annually—revealing the exact APY and dollar difference.

Educational & Banking Disclaimer: This calculator illustrates compounding mathematical models across frequencies. It is not financial advice. Banks determine compounding intervals in their account disclosures. Verify terms with your institution.

Worked Examples

Acceptance Standard: $10,000 at 5% APR for 3 Years (Daily vs. Annual Compounding)

Deposit = $10,000, APR = 5.0%, Term = 3 years.

  1. Daily compounding (n = 365): $10,000 × (1 + 0.05/365)^(1095) = $11,618.22 (APY: 5.1267%).
  2. Monthly compounding (n = 12): $10,000 × (1 + 0.05/12)^(36) = $11,614.72 (APY: 5.1162%).
  3. Annual compounding (n = 1): $10,000 × (1.05)^3 = $11,576.25 (APY: 5.0000%).
  4. Daily advantage over annual: $11,618.22 − $11,576.25 = +$41.97 additional interest.
Final Answer: $11,618.22 Daily vs $11,576.25 Annual

5-Year CD at 4.0% APR ($50,000 Deposit)

Deposit = $50,000, APR = 4.0%, Term = 5 years.

  1. Daily: $50,000 × (1 + 0.04/365)^1825 = $61,069.83 (+$11,070 interest).
  2. Monthly: $50,000 × (1 + 0.04/12)^60 = $61,049.83 (+$11,050 interest).
  3. Annual: $50,000 × (1.04)^5 = $60,832.65 (+$10,833 interest).
  4. Compounding premium: $237.18 extra interest with daily compounding.
Final Answer: $61,070 Daily vs $60,833 Annual

Short 1-Year CD Comparison at 5.5% APR ($100,000 Deposit)

Deposit = $100,000, APR = 5.5%, Term = 1 year.

  1. Daily compounding: $100,000 × (1 + 0.055/365)^365 = $105,653.62.
  2. Annual compounding: $100,000 × (1.055) = $105,500.00.
  3. Difference: $153.62 additional yield in year one.
Final Answer: $105,654 Daily (5.65% APY)

How to Use This Calculator

  1. Enter your deposit capital amount.
  2. Enter the nominal stated annual percentage rate (APR).
  3. Enter the certificate term in years.
  4. Examine the side-by-side comparison grid detailing the exact maturity balance and APY for daily, monthly, quarterly, semi-annual, and annual compounding.

Frequently Asked Questions

Do all banks compound CD interest daily?
No. While most major banks and online institutions compound CD interest daily, some smaller banks and credit unions compound interest monthly, quarterly, or only at maturity. Checking the account disclosure ensures you know which formula is used.
Why does daily compounding earn more than monthly compounding?
Daily compounding recalculates and adds interest to your balance 365 times per year rather than 12 times. This microscopic acceleration in the frequency of interest-on-interest generates a slightly higher Annual Percentage Yield.
Does continuous compounding exist in consumer banking?
Continuous compounding (using Euler’s number e^(r×t)) is a theoretical mathematical limit. In real-world commercial banking, daily compounding (n=365) is the highest frequency applied.
How is this tool differentiated from the standard CD Calculator?
The standard CD Calculator takes a single bank-quoted APY and solves for final maturity and early withdrawal penalties. This CD Compound Interest Calculator takes a nominal APR and reveals the exact dollar variance across all compounding frequencies.
What is the compounding frequency formula for APY?
The statutory formula is APY = (1 + r/n)^n − 1, where r is the nominal annual rate and n is the number of compounding periods per year.

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Reviewed & Authored by: OnlineConvers Quantitative Finance Editorial Team · Last Updated: 2026-10-07
Evaluates compounding frequency sensitivity across standardized financial intervals (n = 365, 12, 4, 2, 1). Evaluates maturity values using FV = P × (1 + r/n)^(n×t) and derives statutory APYs via (1 + r/n)^n − 1. Maintains full 64-bit precision across intermediate exponent calculations. Rounds output values to 2 decimal places.
Citations: The Mathematics of Finance (Zima and Brown (Schaum Outline Series)) · Consumer Financial Protection Bureau Regulation DD: Truth in Savings (CFPB (12 CFR Part 1030))