Daily Compound Interest Calculator
365-day compounding — savings APY math and the credit-card flip side of daily interest.
Formula
Disclaimer: Educational math; banks may use 360-day conventions or tiered rates. Not financial advice.
Disclaimer: This tool is for general informational and estimation purposes only and is not professional financial, tax, accounting or legal advice. All figures are estimates — verify with a qualified professional before making decisions. Read the full disclaimer.
Need daily compound interest calculator results fast? Skip the spreadsheet and get a clear, defensible answer in one step — free, private and instant, recalculating live as you change any input.
About Daily Compound Interest Calculator
Daily compounding is how most US savings accounts, HYSAs and money-market funds actually credit interest: your balance earns a tiny slice every single day, and each slice immediately joins the base. The defaults — $25,000 at a 5% nominal rate — earn $3.42 on day one and compound to a 5.127% APY, the number banks advertise. The honest perspective: daily-versus-monthly is a rounding story (5% nominal: 5.127% daily vs 5.116% monthly APY — about $3/year on $25,000). What daily crediting genuinely changes is FLEXIBILITY: every dollar earns for exactly the days it's present, so parking idle cash for even two weeks between obligations captures real interest — the foundation of T-bill-and-chill cash management and sweep accounts. The same mechanism runs in reverse on revolving debt: credit cards accrue daily on your average balance, so an 18% APR quietly behaves as 19.7% — and a balance carried 'just for a month' accrues from day one, not from the statement date. The interest-per-day output above is a useful lens for both directions: know what each idle (or owed) day is worth and the right behavior becomes obvious.
How to use Daily Compound Interest Calculator
- 1Enter Principal, Annual rate (nominal) (%), Period (years) into the Daily Compound Interest Calculator.
- 2The result is computed automatically using FV = P × (1 + r/365)^(365t) ; APY = (1 + r/365)^365 − 1 — there is no button to press; it updates live as you type.
- 3Change any input to model a different scenario, then use “Copy result link” to share the exact numbers.
Why use Daily Compound Interest Calculator?
- ✓Computes daily compound interest calculator instantly with the correct formula — no spreadsheet needed
- ✓100% free and unlimited, with no sign-up, login or paywall
- ✓Runs entirely in your browser, so the figures you enter are never uploaded or stored
- ✓Shows the formula, a live worked example and references so you can defend the number
Frequently asked questions
Is daily compounding meaningfully better than monthly?+
Barely: 5% nominal yields 5.127% APY daily versus 5.116% monthly — roughly $3/year per $25,000. Choose accounts on the APY (which already bakes in frequency), rate stability and FDIC coverage, not the compounding schedule. The marketing emphasis on 'daily!' exceeds its arithmetic weight.
How is interest calculated if I deposit and withdraw mid-month?+
Daily compounding handles it exactly: each day's interest is computed on that day's closing balance, so money earns for precisely the days it's present. That's why HYSAs suit emergency funds and float — there's no 'minimum period' penalty for moving cash, unlike CDs or FDs.
Why does my credit card charge more than its APR?+
Daily compounding on carried balances: 24% APR ÷ 365 accrues daily and compounds to a 27.1% effective rate — before fees. Interest also starts on new purchases immediately once you carry a balance (grace periods vanish). The cheapest 'investment' at these rates is always clearing the card.
What's the daily interest on $100,000?+
At 5% nominal: $13.70 on day one, drifting up as the balance compounds — roughly $420/month. Inverting that intuition is useful: every month a six-figure sum idles in a 0.01% checking account instead of a 5% HYSA costs a car payment of pure forgone interest.
Related Finance tools
Human Life Value (HLV) Calculator
The economic value of your future earnings to your family — the income-replacement basis for sizing a life-insurance cover.
● LiveTerm Life Insurance Coverage Calculator
How much term-life cover you actually need — replacing income, clearing debts and funding goals, net of existing assets and cover.
● LiveDIME Method Life Insurance Calculator
The DIME formula — Debt + Income + Mortgage + Education — a fast, complete way to size a life-insurance cover.
● Live