Daily Compound Calculator
Daily compounding adds interest to your balance every single day, so each day the growth runs on a slightly larger amount than the day before. The effect looks small on any one day and becomes hard to ignore over months and years, especially when you also feed the account a small deposit daily.
This calculator works in three directions: forward from a lump sum, forward with daily deposits added, and backwards from a savings goal to the daily rate that goal requires.
Same inputs, different compounding frequency
| Frequency | Future value | Interest |
|---|
Estimates only. The math assumes one constant rate, no taxes, no fees, and no withdrawals. Real savings rates move, so treat the result as a planning figure, not a promise.
Quick Answer
Key takeaways
- Daily compounding pays a little more than monthly or annual compounding at the same stated rate, and the result box proves it side by side: $10,512.67 daily against $10,500.00 annually on the worked example.
- APY is the honest comparison number. A 5% rate compounded daily is a 5.13% APY, and accounts should be compared APY to APY.
- Small daily deposits outweigh the compounding detail. Adding $2 a day for 3 years contributes $2,190 of the $3,524.43 final balance in the deposits example below.
- The goal planner runs the formula backwards: turning $10,000 into $15,000 in 365 days needs 0.1111% per day, about 40.57% APR, which tells you at a glance whether a goal is realistic at savings account rates.
- Quick Answer
- Choosing the right tab for your question
- The daily compounding formula, step by step
- Worked example: $10,000 at 5% for one year
- Adding $2 a day: deposits beat frequency
- Working backwards: the rate a goal actually needs
- Daily compound or daily interest: two different questions
- What competing calculators miss
- Frequently Asked Questions
- Add This Calculator to Your Website
Choosing the right tab for your question
Pick the tab that matches the question, because each tab answers a different one. The steps are the same in all three.
Daily compounding answers "what will this lump sum become?" Enter a starting balance, an annual rate, and a number of days. Use it for a single deposit left untouched.
Daily deposits answers "what will I have if I keep adding a little every day?" Enter the starting balance, the rate, the daily deposit, and the years, then choose whether deposits land at the start or the end of each day.
Goal planner answers "what return would I need?" Enter a target, a starting balance, and a deadline in days, and it solves for the required daily rate, APR, and APY.
Read the APY before the headline figure. The future value depends on your inputs, but the APY lets you compare this scenario against any account on the market, including a high yield savings account quoted on a different compounding schedule.
The daily compounding formula, step by step
The formula converts the annual rate into a daily rate, then applies that rate once for every day the money stays invested.
Two details in that formula explain most wrong answers from hand calculations. First, the rate is divided by 100 before it is divided by 365: entering 5 where the formula expects 0.05 inflates the result beyond recognition. Second, the exponent is a day count, not a year count, in this calculator. The textbook form, A = P x (1 + r/365)365t, and the day-count form used here are the same equation with the year split into days, so a 365 day entry and a 1 year entry agree exactly.
United States deposit rules frame why APY matters here. Under Regulation DD, the Truth in Savings rules at 12 CFR Part 1030, banks must disclose APY with a standard calculation and must work interest out on the full daily balance or the average daily balance. That is the legal version of the point this page makes in plain terms: the stated rate alone never tells the whole story, because the compounding schedule is part of the return.
Worked example: $10,000 at 5% for one year
The first tab is pre-filled with this case, and every figure below is what it returns, including the frequency comparison it builds automatically.
| Measure | Result | How it is reached |
|---|---|---|
| Daily rate | 0.01370% | 0.05 divided by 365 = 0.00013699 |
| Future value, daily compounding | $10,512.67 | $10,000 x (1.00013699)365 |
| Interest earned | $512.67 | $10,512.67 minus $10,000 |
| APY | 5.13% | (1.00013699)365 minus 1 |
| Future value, monthly compounding | $10,511.62 | Same rate, 12 periods a year |
| Future value, quarterly compounding | $10,509.45 | Same rate, 4 periods a year |
| Future value, annual compounding | $10,500.00 | Same rate, 1 period a year |
Read the frequency rows honestly: daily compounding beats annual compounding by $12.67 here, and beats monthly by only $1.05. Frequency is a tiebreaker between accounts, not a reason to pick one. The rate, the balance, and the time left invested move the answer far more, and savers checking how long growth takes to snowball can pair this page with the compound interest doubling time calculator, which answers the time side of the same formula.
Adding $2 a day: deposits beat frequency
The deposits tab adds an annuity term to the same formula, because every deposit starts compounding from the day it lands instead of from day one.
| Daily deposits example | End of day | Start of day |
|---|---|---|
| Starting balance | $1,000.00 | $1,000.00 |
| Deposits: $2 a day for 3 years (1,095 days) | $2,190.00 | $2,190.00 |
| Total contributed | $3,190.00 | $3,190.00 |
| Interest earned | $334.43 | $334.75 |
| Future value | $3,524.43 | $3,524.75 |
Two lessons sit in that table. The deposits themselves do most of the work: $2,190 of the $3,524.43 final balance is money put in, not money earned. And the timing choice, which people often agonize over, is worth 32 cents across three years. If your question is the simpler one of what a daily saving habit adds up to before interest, the daily savings calculator covers the deposits side on its own, including working back from a goal to a daily amount.
Working backwards: the rate a goal actually needs
The goal planner solves the compounding formula in reverse, which turns a vague target into a rate you can judge against real accounts.
For the pre-filled case, growing $10,000 into $15,000 in 365 days, the planner returns a required daily rate of 0.1111%, an equivalent APR of 40.57%, and an APY of 50.00%. The APY lands exactly on 50% because the target itself is a 50% gain in one year, which is a useful self-check on the math. It is also the reality check: no insured savings account pays anything near 40% APR, so that goal needs more time, more deposits, or a smaller target. The SEC's investor education site makes the same point with its own tools, and its savings goal calculator at Investor.gov approaches the problem from the contribution side.
Daily compound or daily interest: two different questions
These two pages sit next to each other on this site because the names sound alike, but they answer different questions and their tools only overlap on one mode. This page is about growth over time: a balance compounding daily, with deposits and a reverse goal solver. The daily interest calculator is about the price of one day: it leads with simple interest per day on a balance, the per diem figure used for loan payoffs, late payments, and closing costs, and only offers daily compounding as its second tab. If you need a dollar amount per day, go there. If you need a future balance, a deposit plan, or the rate behind a goal, stay here.
What competing calculators miss
The daily compound tools ranking for this term mostly run the single lump sum formula and stop. Three gaps kept showing up in that set.
Miss 1: no deposits, or deposits with no timing. The strongest competitor found adds a daily contribution, which is genuinely useful, but treats every deposit the same. Real accounts credit deposits at a point in the day, and the start versus end choice changes the result, by $0.32 on the example above. Small, but a tool that hides the choice is quietly making it for you.
Miss 2: no reverse mode. Forward calculators answer "what will I have?" and leave "what would I need?" to guesswork. Typing rates in until the future value hits your target is the slow version of the goal planner tab, which solves it in one step and shows the APR and APY the goal implies.
Miss 3: a day by day table instead of a frequency verdict. One competitor prints a 365 row balance table, which is thorough and hard to use. What a saver choosing between accounts needs is the comparison this page builds automatically: daily, monthly, quarterly, and annual results for the same inputs, with the APY beside them, so the size of the frequency effect is visible at a glance.
One honest limit: everything here assumes the rate never changes. Variable savings rates do change, sometimes several times a year, so rerun the numbers when your bank moves its rate instead of treating an old result as settled.
Disclaimer: this calculator is an educational tool for estimating growth at a constant rate. It is not financial advice, and it does not account for taxes, fees, inflation, or rate changes. For decisions about saving or investing, consult a qualified financial professional.
Frequently Asked Questions
Yes, slightly. On $10,000 at 5% for one year, daily compounding gives $10,512.67 against $10,511.62 for monthly compounding, a difference of $1.05. The rate, the balance, and the time invested move the result far more than the compounding frequency does.
Use 365 for everyday savings estimates. Some banks use a 360 day year, called a banker's year, for certain products, so the first tab includes a days per year selector to match your account terms. Matching the convention gives the most accurate estimate, and the difference between the two is small.
A 5% stated rate compounded daily produces an APY of 5.13%. APY is the effective annual return after compounding, worked out as (1 + 0.05/365) to the power of 365, minus 1. Compare accounts on APY, not on the stated rate, so the compounding schedule is counted fairly.
A large one, mostly because the deposits themselves add up. A $1,000 starting balance with $2 deposited daily at 5% for 3 years grows to $3,524.43 with end of day deposits. You contributed $3,190.00 of that total and earned $334.43 in interest, so the habit supplies most of the growth and compounding adds a meaningful bonus on top.
Use the Goal planner tab, which solves the formula backwards: required daily rate = (target / start) to the power of (1 / days), minus 1. Turning $10,000 into $15,000 in 365 days requires 0.1111% per day, about 40.57% APR and 50.00% APY, which is far beyond savings account rates and a sign the goal needs more time or regular deposits.
Because each deposit earns one extra day of interest. In the deposits formula the start of day option multiplies the deposit term by (1 + daily rate). On $2 a day at 5% for 3 years that extra day per deposit is worth $0.32 in total, $3,524.75 against $3,524.43, so the effect is real but tiny.
No. It is an educational estimate that assumes one constant rate and ignores taxes, fees, and inflation, all of which reduce a real return. For a conservative plan, run the calculation again with a slightly lower rate than the advertised one and treat the lower result as your working figure.
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References
- U.S. Securities and Exchange Commission, Investor.gov, "Compound Interest Calculator" - the SEC's own growth calculator and its explanation of how compounding frequency changes returns. SEC Investor.gov: Compound Interest Calculator. Accessed October 2026.
- U.S. Securities and Exchange Commission, Investor.gov, "Savings Goal Calculator" - the contribution side of goal planning, used to frame the goal planner discussion. SEC Investor.gov: Savings Goal Calculator. Accessed October 2026.
- Consumer Financial Protection Bureau, Regulation DD (Truth in Savings), 12 CFR Part 1030 - the federal rule requiring standardized APY disclosure for deposit accounts. CFPB: Regulation DD, 12 CFR Part 1030. Accessed October 2026.
- Consumer Financial Protection Bureau, Appendix A to Part 1030, "Annual Percentage Yield Calculation" - the official APY formula banks must use. CFPB: Appendix A to Part 1030, APY Calculation. Accessed October 2026.
- Electronic Code of Federal Regulations, Title 12, Part 1030, "Truth in Savings (Regulation DD)" - current regulatory text covering daily balance and average daily balance methods. eCFR: 12 CFR Part 1030, Truth in Savings. Accessed October 2026.
- Bankers Online, Regulation DD Section 1030.7, "Payment of interest" - the rule text requiring interest on the full daily balance at a daily rate of at least 1/365 of the interest rate. Bankers Online: Regulation DD 1030.7, Payment of Interest. Accessed October 2026.
- Federal Reserve Bank of St. Louis, FRASER archive, "Final Regulation DD (Truth in Savings)" - the original Federal Reserve rulemaking record for deposit yield disclosure. FRASER: Final Regulation DD (Truth in Savings). Accessed October 2026.
- Capital One, "APR vs. APY: What's the Difference?" - a plain language comparison of borrowing APR and deposit APY, including why daily compounding lifts APY above the stated rate. Capital One: APR vs. APY. Accessed October 2026.
- Federal Deposit Insurance Corporation, "National Rates and Rate Caps" - the FDIC's published national average deposit rates, the benchmark for judging whether a savings rate is competitive. FDIC: National Rates and Rate Caps. Accessed October 2026.
- U.S. Department of the Treasury, Bureau of the Fiscal Service, "Simple Daily Interest" (Prompt Payment) - the federal government's own daily interest formula, P x (r/360 x d), for interest owed by the day. Bureau of the Fiscal Service: Simple Daily Interest. Accessed October 2026.