Month guides and calendar calculations

Practical explanations for exploring, comparing and planning calendar months.

Monthly calendar generator

Build and read a calendar for any month and year.

Find whether a month contains 28, 29, 30 or 31 days.

Count Monday-through-Friday dates in a particular month.

Count Saturdays and Sundays for any selected month.

Find the boundary dates and weekdays of any calendar month.

Understand full weeks, partial weeks and calendar rows.

Learn when a month contains five Saturdays and five Sundays.

Map January through December to month numbers 1 through 12.

Turn a selected calendar month into a realistic plan.

Calculate month starts and ends for reports and date filters.

Compare length, weekdays, weekends and weekday alignment.

Distinguish calendar months from accounting and contractual periods.

Avoid indexing, overflow and time-zone mistakes in month calculations.