"Interest compounded daily" sounds like magic, but the mechanics are routine. Understanding them removes the mystery — and helps you spot whether an account is as good as it claims.

The Daily Balance Method

Most savings accounts calculate interest on the <strong>daily balance</strong>: each day, the bank takes that day's balance, applies the daily periodic rate (annual rate ÷ 365 or 360), and accrues a tiny amount. Those daily accruals are added up and posted to your account, usually monthly.

Calculation vs Posting

  • •<strong>Calculation:</strong> Happens continuously (often daily) in the background.
  • •<strong>Posting:</strong> The accrued interest is actually added to your balance on a set date — commonly monthly. After posting, the new balance becomes the base for the next cycle, which is what makes it compound.
  • •<strong>Withdrawals:</strong> If you pull money out before posting, you earn less, because the base balance was lower on those days.

Nominal vs Effective (APY)

The bank's nominal rate is the stated annual figure; the effective yield after daily compounding is the APY. Regulation requires deposit accounts to disclose APY so you can compare. A 5% nominal rate with daily compounding shows an APY just above 5.12%.

Why This Matters to You

  1. Compare APY, not the advertised nominal rate.
  2. Keep cash in the account through the posting date to capture accrued interest.
  3. Avoid frequent withdrawals from growth accounts — they lower the base.
  4. Reconcile your statement: posted interest should match the APY times balance, roughly.

None of this changes the formula — it just explains how the label becomes dollars. Model any balance with our compound interest calculator.

<strong>Disclaimer:</strong> The content provided on CompoundFig is for educational and informational purposes only and does not constitute financial, tax, legal, or investment advice. All calculations and projections are hypothetical and based on assumed rates of return, which may not reflect actual market conditions. Individual results will vary. Consult a qualified financial professional before making decisions. CompoundFig does not provide personalized financial recommendations.