The quick method
First decide whether the end date counts. The difference between two dates (end minus start) leaves out one of the two ends: from 1 March to 5 March is 4 days. If both the first and the last day count, as for leave, a rental or a conference, add 1 and you get 5.
Then remove the weekends. Every full week has 5 business days, so for long periods count the full weeks, multiply by 5 and add the business days in the leftover part. Finally, subtract the public holidays that fall on weekdays in the period. The calculator on this page shows the total days, the business days from Monday to Friday, weeks, months and the breakdown in years, months and days at once.
- Days between: end date minus start date.
- Inclusive count: add 1 when both ends count.
- Business days: remove Saturdays and Sundays.
- Working days for a real deadline: also remove public holidays on weekdays.
Try it here: Days Between Dates
Open the full tool pageInclusive or exclusive: which one do you need?
Most mix ups come from this choice. Ask whether the period describes nights or days. A hotel stay from Monday to Friday is 4 nights, which is the exclusive count. A vacation from Monday to Friday is 5 days off, which is the inclusive count. Age, interest and the number of days until an event are usually exclusive; leave, rental days, event durations and inclusive date ranges in contracts (such as from 1 to 31 March inclusive) are inclusive.
In the calculator the default is exclusive. Turn on Include end date to add the last day to both the total and the business day count.
| Situation | Count | Result |
|---|---|---|
| Hotel nights from Monday to Friday | Exclusive | 4 nights |
| Days from Monday until a Friday event | Exclusive | 4 days |
| Leave from Monday to Friday | Inclusive | 5 days |
| Course running Monday to Friday | Inclusive | 5 days |
| Contract period from 1 to 31 March inclusive | Inclusive | 31 days |
Weekends, holidays and different work weeks
A business day normally means Monday to Friday, excluding public holidays. Public holidays differ by country and often by state or region, and some move every year (Easter, Thanksgiving, holidays based on the lunar calendar). That is why the calculator removes only Saturdays and Sundays: for an exact working day count, look up the holidays in your country and subtract the ones that fall on a weekday inside your period.
Over a whole year there are 52 weeks and one or two extra days, so a year has 260 or 261 weekdays; 2026 has 261. After about 10 public holidays, a typical full time year has around 250 working days. Some countries have a different weekend: in several Middle Eastern countries the weekend is Friday and Saturday, and many shops and hospitals work six days a week. In those cases count with the actual working days of the business involved.
Deadlines: 30 days from today, 10 business days
For a deadline like 30 days from today, the usual rule is that today does not count: day 1 is tomorrow. On Monday 26 October 2026, 30 days from today is Wednesday 25 November 2026, 60 days is Friday 25 December and 90 days is Sunday 24 January 2027. Use the Add or subtract mode of the calculator: enter the date, choose Add, type the amount and choose Days, Weeks, Months, Years or Business days.
For business day deadlines, count only weekdays after the start date. Ten business days from Monday 26 October 2026 is Monday 9 November. If a public holiday falls inside the period, move the deadline one weekday later for each holiday.
Legal and official deadlines can follow their own rules. In many systems the day of the triggering event is not counted, and a deadline that ends on a weekend or public holiday moves to the next working day. Contracts may say calendar days, business days or banking days, which are not the same. When the date matters, read the exact wording.
| Start: Monday 26 October 2026 | Result |
|---|---|
| Plus 30 days | Wednesday 25 November 2026 |
| Plus 60 days | Friday 25 December 2026 |
| Plus 90 days | Sunday 24 January 2027 |
| Plus 10 business days | Monday 9 November 2026 |
| Plus 1 month | Thursday 26 November 2026 |
Counting business days in Excel and Google Sheets
Excel and Google Sheets have NETWORKDAYS(start, end, [holidays]), which counts weekdays between two dates and includes both the start and the end date. To match it in the calculator, turn on Include end date. The optional third argument is a range of holiday dates to subtract, for example =NETWORKDAYS(A2,B2,H2:H12) with your holiday list in H2:H12.
For other weekends use NETWORKDAYS.INTL, where the third argument sets the weekend: 7 means Friday and Saturday, 11 means only Sunday. To go the other way and find a deadline, WORKDAY(start, days, [holidays]) returns the date a number of working days after the start, and WORKDAY.INTL does the same with custom weekends. For plain calendar days, subtract the dates (=B2-A2) and add 1 for an inclusive count.
| Goal | Formula |
|---|---|
| Days between, exclusive | =B2-A2 |
| Days between, inclusive | =B2-A2+1 |
| Business days, both ends included | =NETWORKDAYS(A2,B2) |
| Business days minus holidays | =NETWORKDAYS(A2,B2,H2:H12) |
| Date 10 business days later | =WORKDAY(A2,10) |
| Business days with a Friday and Saturday weekend | =NETWORKDAYS.INTL(A2,B2,7) |
Common mistakes and how to avoid them
- Off by one: decide inclusive or exclusive before you count, and write it down in the plan or contract.
- Forgetting holidays: an estimate of 20 business days in December can easily lose two or three days.
- Counting months as 30 days: from 31 January plus one month is the last day of February, not 2 March. The calculator keeps the day of the month where possible and uses the last day of shorter months.
- Leap years: 2028 has 366 days, so a count across February 2028 is one day longer. The calculator uses the real calendar.
- Time zones and cutoffs: a delivery promised in 3 business days often starts the next business day if the order came after the daily cutoff time.
Useful numbers to remember
A year has 365 days, or 366 in leap years such as 2024 and 2028. A common year has 52 weeks and 1 day, a leap year 52 weeks and 2 days. An average month is about 30.44 days and has about 21.7 weekdays. Four weeks are 20 business days, and a quarter has about 65 weekdays before holidays.