Free compound interest (daily) calculator
See how daily compounding grows your money faster than monthly or annual — enter principal, APR, and years, updated live, as you type.
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Hypothetical projection. Excludes taxes, inflation, and fees. Actual investment returns vary.
Results are estimates. Consult a professional.
How the daily compound interest calculator works
Daily compounding applies interest every single day rather than once a month, once a quarter, or once a year. Because earned interest is folded back into the balance 365 times a year instead of 12, the effective annual yield is slightly higher than the stated nominal rate — and slightly higher than monthly compounding at the same rate.
The difference between daily and monthly compounding is small but real. On a $10,000 balance at 7% over 20 years, daily compounding returns $39,179 versus $39,121 for monthly — a difference of $58 (about 0.15%). The gap widens at higher rates and longer horizons.
Worked example: $10,000 at 7% daily compounding for 20 years
Alex deposits $10,000 in an account paying 7% annually, compounded daily. After 20 years with no additional deposits the balance reaches $39,179. The same deposit at monthly compounding would reach $39,121 — daily compounding adds an extra $58.
Daily vs monthly compounding on $10,000
The table compares daily and monthly compounding side-by-side at three rates and three time horizons. All figures start from a $10,000 lump sum with no additional contributions.
| Rate / Horizon | Daily FV | Monthly FV | Difference |
|---|---|---|---|
| 5% — 10 years | $16,487 | $16,470 | $17 |
| 5% — 20 years | $27,181 | $27,126 | $55 |
| 5% — 30 years | $44,812 | $44,650 | $162 |
| 7% — 10 years | $20,138 | $20,097 | $41 |
| 7% — 20 years | $39,179 | $39,121 | $58 |
| 7% — 30 years | $76,123 | $75,923 | $200 |
| 9% — 10 years | $24,596 | $24,514 | $82 |
| 9% — 20 years | $60,496 | $60,072 | $424 |
| 9% — 30 years | $148,780 | $147,440 | $1,340 |
$10,000 lump sum, no additional contributions. Source: NIST and SEC compound interest methodology.
Tips for getting the most from daily compounding
Daily compounding is most common in high-yield savings accounts, money-market accounts, and some certificates of deposit. These tips help you use it effectively.
- Look at APY, not APR — a savings account advertising 7% APR compounded daily has an APY of about 7.25%. Comparing APYs is the only apples-to-apples way to rank accounts with different compounding frequencies.
- Avoid accounts that compound monthly when daily is available at the same rate — the difference grows with balance size. At $100,000 and 5% over 30 years, daily compounding adds about $1,620 versus monthly.
- Use daily compounding for emergency funds and cash savings — high-yield savings accounts typically compound daily, making them a good fit for liquid cash where you can't take market risk.
- Reinvest interest automatically — in savings accounts the interest is credited to the balance automatically. In manually managed accounts, leaving interest to accumulate rather than withdrawing it preserves the daily compounding effect.
- Don't over-optimise frequency when rate matters more — a 0.5% rate advantage beats switching from monthly to daily compounding by a wide margin. Rate first, then frequency.
Accuracy and limitations
This calculator applies the standard daily compounding formula using 365 days per year. It assumes a fixed nominal annual rate for the full term and that no withdrawals are made. It does not account for taxes on interest, account fees, leap-year day counts, or changes in the interest rate. Some banks use a 360-day year for commercial loans, which would produce slightly different results.
Results are for educational and planning purposes only and do not constitute financial advice. Consult a qualified financial adviser before making savings or investment decisions.
Daily compounding terms defined
About this daily compound interest calculator
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