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How to Count the Days Between Two Dates

By Dr. Ahmed Mortuza Saleque · Updated · How we check our content

The short answer

To count the days between two dates, subtract the earlier date from the later one. January 1 to March 1, 2027 is 59 days: 31 in January plus 28 in February. Add 1 if you need to count both the first and the last day.

Open the Date Calculator →

The day-of-year method

Days in each month and running total (non-leap year).

MonthDaysDay of year at month end
January3131
February2859
March3190
April30120
May31151
June30181
July31212
August31243
September30273
October31304
November30334
December31365

Give each date its day number within the year, then subtract. The table shows the day number of the last day of each month in a normal year; add 1 from March onwards in a leap year.

Worked example

  1. March 10: February ends on day 59, so March 10 is day 59 + 10 = 69.
  2. September 25: August ends on day 243, so September 25 is day 243 + 25 = 268.
  3. Subtract: 268 − 69 = 199 days between the two dates.

Check any pair of dates with the date calculator, which also adds or subtracts days from a date.

When the dates are in different years

Count the days left in the first year, add 365 or 366 for each full year in between, then add the day number in the final year. From November 10, 2026 (day 314) to February 8, 2027 (day 39): 365 − 314 = 51 days left in 2026, plus 39, which is 90 days.

A year is a leap year if it divides by 4, except century years, which must divide by 400. So 2028 is a leap year, 2100 is not and 2000 was.

Inclusive or exclusive?

Subtracting dates counts the nights between them, so Monday to Friday is 4 days. If both the first and the last day count, as with hotel stays billed per day, event lengths or some legal deadlines, add 1 to get 5. Contracts usually say which rule applies.

Business days

Every full week contains 5 working days. Divide the total days by 7, multiply the whole weeks by 5, then count the leftover weekdays. From Monday, November 2, 2026 to Monday, November 30, 2026 is 28 days, exactly 4 weeks, so 20 business days. Subtract public holidays: in the United States, Thanksgiving on November 26 leaves 19.

Excel and Google Sheets formulas

With the start date in A1 and the end date in B1.

What you wantFormula
Days between=B1 - A1 or =DAYS(B1, A1)
Business days (Monday to Friday)=NETWORKDAYS(A1, B1)
Whole weeks=INT((B1 - A1) / 7)
Whole months=DATEDIF(A1, B1, "M")
Date 90 days later=A1 + 90

NETWORKDAYS counts both the start and end dates and accepts a list of holidays as a third argument. For hours and minutes between two times, use the time duration calculator.

Common questions

How many days are there between two dates?

Subtract the earlier date from the later one. Using day-of-year numbers, March 10 (day 69) to September 25 (day 268) is 199 days in a normal year.

How do I count weeks between two dates?

Count the days and divide by 7. 59 days is 8 weeks and 3 days.

What date is 90 days from today?

Add 90 to today's date. From November 10, 2026 that is February 8, 2027.

Does the count include the end date?

Simple subtraction does not. Add 1 if you need to include both the first and the last day.

Calculators for this article

Sources

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