Day counts settle real questions: a contract deadline, a notice period, how many nights a booking covers, how long is left on a visa. Two details decide the answer, and people disagree about both — whether the final day counts, and whether weekends do. This calculator reports both readings at once, so you can match whichever convention your agreement uses. For an exact age from a date of birth, use the age calculator; to price the drive you are counting down to, the fuel cost calculator.
A worked example: May 20 to September 25, 2026
Take the calculator's own default range. From May 20 to September 25, 2026 the raw count is 128 days. The same span reads as 18 weeks and 2 days, or as 4 months and 5 days on the calendar — three different descriptions of one identical gap. Of those 128 days, 92 fall on weekdays and 36 on weekends. Counting the end day as well makes it 129 days rather than 128. Every figure on this page comes from the same function the calculator above runs, so you can reproduce each one by entering the dates yourself.
Date to date example: January 1 to July 4, 2026
Enter January 1, 2026 as the start date and July 4, 2026 as the end date, with Include end day set to No. The calculator returns 184 days. You can check it by hand: January through June add 31 + 28 + 31 + 30 + 31 + 30 = 181 days, which brings you to July 1, and July 1 to 3 add 3 more. The same gap is 26 weeks and 2 days, 6 months and 3 days on the calendar, or 4,416 hours.
Of those 184 days, 132 are weekdays and 52 fall on a Saturday or Sunday. The weekday count still includes New Year's Day, because public holidays are not removed automatically.
Set Include end day to Yes and the total becomes 185 days. The business-day count stays at 132, because July 4, 2026 is a Saturday: the extra day is a weekend day, so weekend days rise to 53.
Days versus calendar duration
There are two natural ways to express a gap between dates. The raw day count is a single number — useful for deadlines, interest, and shipping windows. The calendar duration expresses the same gap as months and days, which reads more naturally for describing how long something lasted. Both describe the identical span; they just group the days differently. Calendar months are the slippery one, because they are not equal in length: the 128 days above span four months and five days, but the same 128 days starting in a different season would land on a different month-and-day figure. Our calculator shows each so you can pick whichever fits your situation.
Counting business days
For contracts, payroll, and project planning, weekends usually do not count. We tally only Monday through Friday across your range, which is why the business-day total is smaller than the calendar total — 92 weekdays out of 128 days in the example above, a little over 70%. Keep in mind that public holidays are not removed automatically, since they vary by state and country; subtract any that fall inside your range for a true working-day figure. For a US range, that usually means subtracting between one and three federal holidays per quarter.
Whether to include the end day
Some counts are inclusive and some are exclusive. Booking a hotel from the 20th to the 25th is usually five nights, not six, because the checkout day does not count. A rental or subscription might count both endpoints. The difference is always exactly one day — 128 against 129 in the example above — which sounds trivial until it decides whether a filing lands inside a 30-day window. The include-end-day toggle lets you switch between these conventions so your total matches the way your particular agreement defines the period. To find an exact age from a date of birth, use the age calculator.