Daily Compound Interest Calculator

Calculate the final amount and interest earned when interest compounds daily over a set number of days. Free, instant, no signup.

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days
Formula: A = P × (1 + r/365)^days
  • P = principal
  • r = annual rate (decimal)
  • days = number of days

How to use the Daily Compound Interest Calculator

  1. Enter your values. Fill in the fields with your numbers.
  2. Calculate. Press Calculate to run the daily compound interest calculator.
  3. Use the result. Copy the result or try a related tool next.

Why use our Daily Compound Interest Calculator

Instant results. Enter your figures and the daily compound interest calculator returns an answer in seconds.
Free & private. Runs in your browser — no signup, and nothing is sent to a server.
Accurate. Uses standard formulas so you can rely on the numbers.

Free to use — premium coming soon

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About the Daily Compound Interest Calculator

The Daily Compound Interest Calculator shows how a balance grows when interest is added to the principal every single day instead of monthly, quarterly, or once a year. You enter a starting amount, an annual interest rate, and a time period, and it projects the future value plus the total interest earned. Daily compounding is the model most online savings accounts, money market accounts, and certificates of deposit use behind the scenes, so this tool is the right fit when your bank advertises that interest is calculated daily and credited monthly. It turns a rate on paper into a concrete dollar figure for any horizon you choose.

Use this calculator when you want to compare real returns rather than headline rates. Because daily compounding adds 365 interest events per year, it edges out monthly or annual compounding on the same nominal rate, though the gap is usually small at today's rates. For example, $100,000 at 3% earns roughly $3,045 over a year compounded daily versus about $3,042 compounded monthly, a difference of only a few dollars. The calculator makes that comparison visible, which helps when you are deciding between accounts, estimating CD maturity values, or setting a realistic savings goal for a down payment or emergency fund.

Under the hood the tool uses the standard daily compounding formula A = P(1 + r/365)^(365t), where A is the ending balance, P is the principal, r is the annual rate as a decimal, and t is the number of years. It converts your annual rate to a daily rate by dividing by 365, raises that growth factor to the power of the number of days, and multiplies by your starting balance. If you add regular contributions, it layers the future value of those deposits on top using the annuity portion of the formula, so each deposit also earns daily interest for the days it stays invested.

Every calculation runs entirely in your browser, so the amounts, rates, and goals you type are never uploaded, logged, or stored on a server. The results are mathematical projections based only on the numbers you provide; they assume a fixed rate and ignore taxes, fees, promotional rate changes, and whether your bank uses a 360-day rather than 365-day year. Treat the output as a close planning estimate rather than a guaranteed bank statement. For an exact figure, confirm your account's stated APY and compounding convention, since APY already bakes in the compounding effect this tool demonstrates.

Frequently asked questions

What formula does this daily compound interest calculator use?

It uses A = P(1 + r/365)^(365t), where P is the principal, r is the annual rate as a decimal, and t is the number of years. The rate is divided by 365 to get a daily rate, then compounded once for each day in the period.

Does daily compounding really earn much more than monthly?

Only a little. On a $100,000 balance at 3%, daily compounding earns about $3,045 a year versus roughly $3,042 with monthly compounding, a difference of under $4. The interest rate itself matters far more than how often it compounds.

Should I compare accounts by compounding frequency or by APY?

Compare by APY. The annual percentage yield already includes the effect of daily compounding, so it reflects your true yearly return and lets you compare accounts on equal footing without doing the math yourself.

Should I use 365 or 360 days for the calculation?

Most consumer savings accounts and CDs use a 365-day year, which this calculator assumes. Some lenders use a 360-day year, which produces a slightly larger daily rate and marginally more interest, so check your account's terms if you need an exact match.

Can I include regular deposits in the projection?

Yes. When you add recurring contributions, the calculator compounds each deposit daily for the time it remains invested and adds that to the growth of your starting balance, which reflects how steady saving accelerates your total.

From our blog

Time and a Half, Explained: How to Check Your Overtime Pay in Under a Minute

By the Super Simple Digital Tools Team · Updated June 2026

Overtime is one of the most commonly miscalculated parts of a paycheck, partly because the rules sound simpler than they are. The core idea is that hours beyond a threshold are worth more, but the threshold, the multiplier, and the definition of your pay rate all matter. Before trusting any number, it helps to separate three things: how many hours are regular, how many are overtime, and what hourly rate the premium is built on. Get those three inputs right and the rest is arithmetic the calculator handles for you.

The federal baseline is the 40-hour workweek. Once a non-exempt worker passes 40 hours in a single seven-day workweek, every additional hour must be paid at no less than 1.5 times the regular rate. A crucial detail people miss is that overtime is measured by the workweek, not the pay period. If you work 30 hours one week and 50 the next, you are owed 10 hours of overtime even though your two-week total is exactly 80. Employers cannot legally average the two weeks to avoid the premium.

Many states layer extra protection on top of the federal floor. California is the best-known example: it requires overtime after 8 hours in a single day, not just after 40 in a week, and it adds double time once you cross 12 hours in a day or work beyond 8 hours on a seventh consecutive workday. That is why a single long shift can earn overtime even in a short week. When you model these situations, switch the multiplier to 2x for the double-time portion and 1.5x for the rest, then add the results together.

The 'regular rate' is the input most likely to trip people up. Federal rules define it as more than your base wage; it can fold in nondiscretionary bonuses, shift differentials, and certain other earnings, then divide by total hours to find the true hourly figure the premium is based on. If you only worked a flat hourly job with no bonuses, your base rate is your regular rate. If your pay is more complex, treat the calculator's result as a close estimate and compare it against your pay stub line by line.

Finally, remember the number you see is gross pay. Overtime is still subject to income tax and payroll withholding, so your take-home increase is smaller than the headline figure. A temporary federal provision starting with the 2025 tax year lets eligible workers deduct a portion of qualified overtime premium pay at tax time, but that is a filing benefit, not something deducted from each check. Use the calculator to confirm you were paid correctly first, then plan around the after-tax amount.

  • Always calculate overtime per workweek, never across a two-week pay period, since the FLSA prohibits averaging two weeks to dodge the premium.
  • If you earn nondiscretionary bonuses or shift differentials, recompute your true regular rate before entering it, as your base wage alone may understate what you are owed.
  • Check your state's rules: in places like California, use the double-time (2x) option for hours past 12 in a day or beyond 8 on a seventh straight workday.
  • Compare the calculator's gross result against the overtime line on your pay stub, and if they differ, raise it with payroll with your hours and rate written down.

Read the full guide →

Tool by the Super Simple Digital Tools Team. Reviewed by our editorial team. Free to use, no signup required.

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