Daily Compound Interest Calculator for Savings Accounts - APY & Growth
Calculate daily compound interest on a savings balance with optional recurring contributions. Enter starting balance, annual rate, years, and contribution frequency to see estimated APY, total interest, and a Day, Month, or Year growth schedule you can download as CSV or PDF.
Savings details
Interest compounds daily (365). Contributions post at the end of each selected period.
Optional recurring deposit amount.
Your estimated savings
Final balance, contributions, and interest under daily compounding.
Estimated balance
$16,486.65
$10,000 contributed · $6,487 interest · 5.127% APY
Balance growth over time
Compare ending balance with interest earned each year. Add a contribution to plot deposits too.
Growth schedule
Deposit and interest posted each period under daily compounding. Deposits are added at the end of each contribution period.
| Year | Deposit | Interest | Cumulative deposits | Cumulative interest | Ending balance |
|---|---|---|---|---|---|
| Year 1 | $0.00 | $512.67 | $10,000.00 | $512.67 | $10,512.67 |
| Year 2 | $0.00 | $538.92 | $10,000.00 | $1,051.63 | $11,051.63 |
| Year 3 | $0.00 | $566.62 | $10,000.00 | $1,618.22 | $11,618.22 |
| Year 4 | $0.00 | $595.63 | $10,000.00 | $2,213.86 | $12,213.86 |
| Year 5 | $0.00 | $626.19 | $10,000.00 | $2,840.03 | $12,840.03 |
| Year 6 | $0.00 | $658.27 | $10,000.00 | $3,498.31 | $13,498.31 |
| Year 7 | $0.00 | $692.00 | $10,000.00 | $4,190.34 | $14,190.34 |
| Year 8 | $0.00 | $727.51 | $10,000.00 | $4,917.84 | $14,917.84 |
| Year 9 | $0.00 | $764.82 | $10,000.00 | $5,682.64 | $15,682.64 |
| Year 10 | $0.00 | $804.01 | $10,000.00 | $6,486.65 | $16,486.65 |
Methodology and limitations
Last reviewed:
Methodology
Uses daily compounding with 365 periods per year and optional recurring contributions at weekly, biweekly, monthly, quarterly, or yearly frequency. Deposits are added at the end of each contribution period, and the daily ledger is aggregated into Day, Month, and Year schedules you can export as CSV or PDF.
Limitations
Does not model bank posting dates, tiered rates, leap days, or fees.
Official sources
How Daily Compound Interest Works
Method used
This calculator compounds interest daily on the running balance, adds recurring contributions at the end of each selected contribution period, and reports estimated balance, total contributed, interest earned, effective APY, and Day/Month/Year schedules you can export.
Daily rate = APR ÷ 365; balance grows by (1 + daily rate) each day; contribution added at the end of each weekly, biweekly, monthly, quarterly, or yearly period
Practical example
You put $1,500 in a high-yield account at 4.5% APR compounded daily. After one year with no extra deposits, the balance grows to about $1,568 (effective APY ≈ 4.60%)—a small edge over monthly posting at the same nominal rate.
- $1,500 starting balance at 4.5% APR
- Daily compounding for 1 year
- No recurring contributions
The output shows estimated balance, total contributed, interest earned, effective APY, a balance-versus-interest chart, and a downloadable Day, Month, or Year schedule.
Assumptions
- Compounding occurs 365 days per year (non-leap model).
- Recurring contributions are added at the end of each contribution period.
- Rate stays constant; no taxes, fees, or bank cut-off times are deducted.
What this includes
- Daily compounding projection, selectable contribution frequency, interest earned, APY equivalent, growth chart, and CSV/PDF schedule exports.
What this excludes
- Variable rates, withdrawal schedules, tax-deferred account rules, bank compounding cut-off times, and intra-period contribution timing differences.
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Frequently Asked Questions
What is the daily compound interest formula?
Future value with daily compounding is FV = PV × (1 + r/365)^(365 × t), where PV is principal, r is the annual rate as a decimal, and t is years. Example: $10,000 at 4.5% for one year → about $10,460, because APY = (1 + 0.045/365)^365 − 1 ≈ 4.60%. Each day interest is calculated on the running balance. This calculator shows APY, total interest, and growth snapshots.
How is daily compounding different from monthly?
Daily compounding applies interest 365 times per year; monthly applies it 12 times. At 5% nominal, daily APY is about 5.127% versus 5.116% monthly. On $10,000 for one year that is only a few dollars difference, but the gap widens with larger balances and longer horizons. Credit cards also use daily rates - a 22% APR card accrues interest much faster than a 4.5% savings account.
When do banks use daily compounding?
Many high-yield savings accounts, money market accounts, and some CDs compound daily while crediting interest monthly. Credit cards often use daily periodic rates on balances. Investment accounts may compound daily inside funds even when you see monthly statements. Always check whether the quoted rate is APR or APY and how often interest posts to your account.
How do I use this as a savings account calculator compounded daily?
Enter starting balance, annual rate, and time horizon with daily (365) compounding. Example path: $25,000 at 4.5% plus about $200 monthly deposits for five years can grow toward the mid-$40,000s depending on when deposits post. Results show final balance, interest earned, and APY - compare against monthly compounding at the same quoted rate.
Can I change how often I contribute?
Yes. Enter a contribution amount and choose weekly, every 2 weeks, monthly, quarterly, or yearly frequency. Deposits are modeled at the end of each contribution period while interest still compounds daily on the running balance. Changing frequency changes how quickly new principal starts earning daily interest.
Can I download the growth schedule as CSV or PDF?
Yes. Switch the table between Day, Month, and Year views, then use Download CSV or Download PDF to export exactly what you see. The CSV opens in Excel, Google Sheets, or Numbers so you can sort, filter, or chart your own scenarios, and each row lists the period, starting balance, contributions, interest earned, and ending balance. The PDF is a branded, printable report with your inputs, summary, growth chart, and schedule. Day-view exports can be long, so the tool warns you before generating a very large PDF while the CSV stays available for the full detail.
Does this calculator show simple interest comparison?
Yes. Results include a simple-interest comparison using the same principal, contributions, and nominal rate without compounding. On $10,000 at 4.5% for one year, simple interest is $450 versus about $460 with daily compounding - the gap grows each year as interest earns interest.