Weekend days, weekdays and the count of each weekday in a month
Drawing up a monthly rota, or counting how many sessions a twice-a-week class will actually hold, starts with knowing how many of each weekday the month contains. Pick a year and a month and you get the number of weekend days, the number of weekdays, the length of the month, the weekday of the 1st and of the last day, and a table showing how often each of the seven weekdays occurs.
Why some weekdays occur five times
A week is 7 days, so a 28-day month gives each weekday exactly four occurrences. At 29 days one weekday gets a fifth, at 30 days two do and at 31 days three do, and which ones depends on the weekday of the 1st. The count simply walks from the 1st to the last day, and leap years follow the rule that a year divisible by 4 qualifies unless it is divisible by 100 without also being divisible by 400. Dates are handled by their components in Coordinated Universal Time, so the answer does not change with the reader time zone.
As of October 2026 no external table or official recommended value is used. Weekend means Saturday and Sunday only, and neither the number of weekend days between two dates nor working days adjusted for public holidays is covered. Employer-specific rest patterns, such as working Saturdays or rotating shifts, are also not applied. Years from 1900 to 2200 are supported.
Frequently asked questions
Yes. A 31-day month has three weekdays occurring five times and a 30-day month has two, while only a 28-day February has all seven occurring exactly four times. The result names which ones they are.
No. Only Saturday and Sunday count as weekend here and everything else is counted as a weekday. Working days adjusted for public holidays or substitute holidays are not covered.
February has 29 days in a year divisible by 4, except that a year divisible by 100 must also be divisible by 400. So February 1900 counts as 28 days while February 2000 and February 2028 count as 29.