Compounded 365×/year
Daily Compound Interest
How most high-yield savings accounts, money markets, and online banks actually post interest.
Live·Updates on every change
Future value
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After
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Contributed
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Principal + deposits
Interest earned
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Effective APY
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Growth over time
Principal, contributions, and interest — stacked year by year.
PrincipalContributionsInterest
Year-by-year breakdown
Opening balance, deposits, interest, closing balance.
Show table
Year-by-year breakdown
Opening balance, deposits, interest, closing balance.
| Year | Opening | Net flows | Interest | Closing |
|---|
The math
n = 365, every year.
The formula is A = P(1 + r/365)365t. Compared with monthly compounding, daily gives a tiny APY bump — a few basis points — because interest earns interest sooner.
APY by compound frequency
At a nominal 5% annual rate:
| Annually | 5.000% |
| Quarterly | 5.095% |
| Monthly | 5.116% |
| Daily | 5.127% |
FAQ
Frequently asked
What does daily compounding mean?
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Interest is calculated and added to the balance every day — 365 times a year. The next day's interest is based on the slightly larger new balance.
Does daily beat monthly by much?
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At 5%, daily compounding gives an APY of 5.127%; monthly gives 5.116%. The gap is about 0.01 percentage points — meaningful on $1M, trivial on $1,000.
Which accounts actually compound daily?
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Most US high-yield savings accounts, money market accounts, and many online CDs compound daily. Check the APY line on the account disclosure — that's the number that already includes the compounding.
What rate should I use?
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Enter the account's stated interest rate (the nominal rate, sometimes labelled APR) and keep compounding on daily — the calculator works out the APY for you. If the bank only quotes an APY, enter it with annual compounding instead. Entering an APY with daily compounding counts the compounding twice and overstates your growth.
Start compounding, keep compounding.
Open the calculator, change one number, and watch the long tail.