Days count between dates

how many days in between two dates

A count of days between dates is a number you can report, check, and put in a cell. It is not a feeling that “it has been about three months.” From the 10th to the 20th the ordinary count is 10. Inclusive dates in that same window number 11. Pick one convention and keep it next to the number, because a bare “10” does not say which convention produced it.

Count days between dates the same way for a long span as for a short one. Crossing a year boundary does not change the method. Crossing a leap day does change the total by one compared with a year that has no February 29 in the window. The count still comes from the two dates, not from multiplying months by thirty.

When someone asks for the count of days between dates, ask whether nights, weekdays, or elapsed 24-hour periods are what they meant. Those are neighboring numbers. They are not the same number. A date has no clock time. Two consecutive dates are one day apart on the calendar even if a clock change made the local night shorter or longer.

Ordinary count: subtract dates. Start is out, end is the day you land on. Inclusive count: subtract, then add one, so both printed dates belong to the range. Weekday count: drop Saturday and Sunday after you have the date list or an equivalent week method.

Business-day count: drop the weekend and then drop the holidays that apply to that workplace or country.

Count days between dates in Excel

Excel stores a date as a serial number, so a cell that looks like a date is already something you can subtract. To count days between dates in Excel, put the start in one cell and the end in another, then subtract the start from the end. If A2 holds the earlier date and B2 the later date, B2-A2 is the ordinary days count. Format the result as a number, not as a date, or Excel may display a date that is not what you meant.

The DAYS function does the same job with named arguments: DAYS of the later date minus the earlier date. DATEDIF with the unit "d" also returns a whole-day count from start to end. Those three routes — subtraction, DAYS, and DATEDIF with "d" — are three spellings of the same calendar difference. They do not include both endpoints unless you add one yourself.

An Excel count days between dates that uses NETWORKDAYS is no longer a calendar count. NETWORKDAYS counts work days. Use it only when the question is work days. A holidays list, if you pass one, must be the list that actually applies. Excel will not invent your public holidays.

A spreadsheet will count what you typed. It will not notice that you meant “through Friday” while the formula meant “until Friday.”

What the count refuses to mean

The days count is not age in years. Age in completed years waits for a birthday, and a year is 365 or 366 days. The count is not “how many months” either. Months differ in length, so 90 days is not three months on a calendar, and three calendar months is not always 90 days.

If you need weeks, divide the day count by seven and keep the remainder as days. If you need a signed result, do not take the absolute value until you know direction does not matter. A count of minus three days is a real answer when the end date is earlier than the start.