This calculator turns an annual rate into interest per day and adds it up over the days you choose. It is simple interest, calculated on the starting balance only, which is how accrued interest is quoted on most statements. If you want each day's interest to earn interest of its own, use the daily compound interest calculator .
| Day | Interest | Accrued |
|---|
The table above is the accrual schedule: $10,000.00 at 6.00% earns $1.6438 every day, for a total of $49.32 over 30 days and a balance of $10,049.32 at the end. Because this is simple interest, each day's figure is identical — the balance the interest is calculated on never changes.
Three steps get you from an annual rate to a total accrued amount. First, divide the annual rate by the days in the year to get a daily rate: 6.00% ÷ 365 = 0.01644%. Second, multiply that daily rate by the balance to get the interest per day: $10,000.00 × 0.01644% = $1.6438. Third, multiply the per-day figure by the number of days: $1.6438 × 30 = $49.32.
Interest = Balance × Rate ÷ Days-in-year × Days
This applies whenever interest is quoted on the original balance — accrued interest on statements, per-diem figures, and similar day-count calculations.
The basis is the number of days the agreement treats a year as having, and it changes the daily rate. On $10,000.00 at 6.00% for 30 days, a 365-day basis gives a daily rate of 0.01644% and a total of $49.32. A 360-day basis gives a slightly larger daily rate of 0.01667% and a total of $50.00 — $50.00 vs $49.32 on the same balance and rate. The 360-day convention is common in commercial lending; most consumer accounts use 365.
Daily interest, as calculated on this page, is figured on the original balance every day and never joins that balance. Daily compound interest adds each day's interest to the balance before the next day is calculated, so the amount grows a little faster. On $10,000.00 at 6.00% the difference is small over 30 days ($49.32 vs $49.43) but adds up over a year ($600.00 vs $618.31). For that comparison, use the daily compound interest calculator .
Looking at a real savings account quoted in APY instead of a nominal rate? The savings account interest calculator takes the APY directly and produces a month-by-month statement.
Divide the annual rate by the number of days in the year to get a daily rate, then multiply by the balance. On $10,000.00 at 6.00%, the daily rate is 0.06 ÷ 365 = 0.01644% and the interest is $1.6438 per day. Over 30 days that accrues to $49.32.
Divide by 365, or by 360 if the agreement uses a 360-day year. 6.00% becomes 0.01644% per day on a 365-day basis and 0.01667% on a 360-day basis, which on $10,000.00 is $1.6438 against $1.6667 per day.
Interest that has built up on a balance but has not yet been paid or charged. $10,000.00 at 6.00% accrues $147.95 over 90 days. The same arithmetic applies whether the balance is one you earn on or one you owe on; only the direction changes.
No. Daily interest, as calculated here, is charged or earned on the original balance every day. Daily compound interest adds each day's interest to the balance before the next day is calculated. On $10,000.00 at 6.00% the two differ by about a dime after 30 days ($49.32 vs $49.43) and by $18.31 after a year ($600.00 vs $618.31).
A 360-day divisor makes each day's interest slightly larger: 6.00% ÷ 360 is 0.01667% per day instead of 0.01644%. On $10,000.00 for 30 days that is $50.00 rather than $49.32. The basis is set out in the account or loan agreement; the calculator lets you pick either.
Calculate daily compound interest with contributions and see year-by-year growth and APY.
Enter the APY, a starting balance and a monthly deposit to get a month-by-month statement.
Enter deposit, APY and term to see interest earned and value at maturity.