CD Calculator Formula

Understand the math behind the cd calculator. Each variable explained with a worked example.

Formulas Used

Value at Maturity

maturity_value = deposit * pow(1 + apy / 100, years)

Interest Earned

interest_earned = maturity_value - deposit

Variables

VariableDescriptionDefault
depositDeposit Amount(USD)10000
apyAPY (Annual Percentage Yield)(%)5
term_monthsTerm(months)12
yearsDerived value= term_months / 12calculated

How It Works

CD Interest Formula

Maturity Value = Deposit × (1 + APY/100)^years

CDs typically offer higher rates than savings accounts in exchange for locking up your money for a fixed term.

Worked Example

$10,000 CD at 5% APY for 12 months.

deposit = 10000apy = 5term_months = 12
  1. 01Value = $10,000 × (1.05)^1 = $10,500
  2. 02Interest earned = $500

Frequently Asked Questions

What happens if I withdraw early?

Early withdrawal typically incurs a penalty of 3-12 months of interest, depending on the CD term.

Learn More

Guide

Understanding APR vs. APY

Learn the difference between APR and APY, why they matter for loans and savings, and how to use each when comparing financial products. Includes formulas and real-world examples.

Ready to run the numbers?

Open CD Calculator