APY Calculator

Worked example

Example 1: 4.75% APR compounded monthly → APY slightly above 4.85%. Example 2: $10,000 at 5.00% APY for one year → about $10,500 before taxes.

When to use this

• Comparing savings account APYs.
• Converting APR to APY.
• Projecting one-year growth.
• Checking CD compounding assumptions.
• Teaching compounding frequency effects.

Common examples

• 4.75% APR monthly compound → APY slightly higher.
• $10,000 at 5% APY for one year → ~$10,500 before tax.
• Daily vs monthly compounding comparison on the same APR.
• CD APY vs savings APY at equal principal.
• Convert advertised APY back to approximate APR.

Common mistakes

• Comparing APR to APY directly.
• Ignoring compounding frequency.
• Forgetting taxes on interest.
• Assuming APY is guaranteed variable-rate forever.
• Mixing promotional teaser APYs with base rates.

How it works

Converts between APR and APY given compounding frequency, or projects ending balance from principal and APY. Useful for comparing savings accounts and CDs.

Limitations

Estimates only for educational purposes. Not financial, tax, or legal advice. Verify figures with your lender, advisor, or official IRS/SSA sources before making decisions.

Privacy and file handling

Your data stays on your device and is not uploaded.

Formula or method

APY = (1 + r/n)^n − 1 for nominal APR r with n compounding periods per year. Ending balance ≈ principal × (1 + APY)^years for annual APY application.