Monthly Calendar Generator
Select a month and enter a year to generate a Sunday-first calendar showing every date in that month.
Monthly Calendar Creation Tool
Monthly Calendar Generator Formula
Where:
- \(Y\) — the selected year.
- \(M\) — the selected month as a zero-based index: January is \(0\), December is \(11\).
- \(w\) — the weekday of the first day, numbered Sunday \(0\) through Saturday \(6\).
- \(D\) — the number of days in the selected month.
- \(d\) — a date from \(1\) through \(D\); its column is numbered Sunday \(0\) through Saturday \(6\).
The calculator uses JavaScript date functions to find the first weekday and the final date of the month. It then places each numbered date in a seven-column calendar grid.
Monthly Calendar Generator – Calculation Example
Example: select September for Month and enter 2026 for Year. September 1, 2026, is a Tuesday, and September has 30 days.
\[w=2,\qquad D=30\]
Two cells are left empty before Tuesday, September 1. The final date falls in column \[(2+30-1)\bmod 7=3\], which is Wednesday.
Result: a September 2026 calendar running from Tuesday the 1st through Wednesday the 30th, with Sunday as the first column.
How to use the calculator
- Choose the desired Month from the January–December list.
- Enter a whole-number Year. The field initially shows the current year, and the Month field initially shows the current month.
- Read the Calendar result. Each row represents a week, with columns labeled Sunday through Saturday.
- Change either field to view another month. The calendar is regenerated from the selected values.
To plan around a date, find its number in the grid and read the weekday at the top of its column. Blank cells before the 1st and after the last date are placeholders, not dates in the neighboring months.
Understanding the monthly calendar
A monthly calendar arranges dates by week so you can see both their order and their weekdays. The first row does not necessarily begin with the 1st: if the month starts on a Thursday, the Sunday, Monday, Tuesday, and Wednesday cells in that row are blank. The same rule applies at the end of the final row.
Month lengths vary. April, June, September, and November have 30 days; most other months have 31. February has 28 days in a common year and 29 in a leap year. The generator determines the length of the selected month from its date calculation, so you do not need to enter the number of days yourself. If you need just that count, use the Days in Month calculator.
The layout always begins with Sunday and ends with Saturday. For September 2026, the first week has two blank cells followed by dates 1–5. The final week contains September 27–30, followed by three blank cells. This makes it possible to identify a date’s weekday without counting forward from the start of the month. For a single date outside a monthly view, try the Day of the Week calculator.
Assumptions and practical limitations
- Fixed week order: the headings are always Sunday through Saturday. The generator does not switch to a Monday-first layout based on your location.
- Dates only: the result does not mark public holidays, appointments, weekends, or today’s date. You can use the grid as a reference, but it does not store plans or events.
- Calendar year: the year field accepts values starting at 1, but JavaScript’s date constructor interprets years 0–99 as 1900–1999. As a result, a selection in years 1–99 may show incorrect weekdays or month lengths for the year you intended. Use particular care with historical dates.
- One month at a time: this view shows weekdays and dates, not the number of days between two events. For an interval that may cross months, use the Days Between Dates calculator.
For ordinary modern years, the calendar is a quick way to check where a month starts and ends before setting a schedule. If you need a paper copy, use your browser’s print function; the appearance of the printed page depends on your browser and printer settings.
Frequently Asked Questions
How can I work out a monthly calendar by hand?
Start with a date whose weekday you know, then count forward to the first day of the month. Each elapsed day moves the weekday forward by one; after Saturday, return to Sunday. Write the dates in seven columns, starting the 1st under its weekday. Remember to include February 29 when counting through a leap year.
How do I tell whether February has 29 days?
In the Gregorian calendar, a year is a leap year if it is divisible by 4, except century years must also be divisible by 400. Thus 2028 and 2000 are leap years, but 1900 and 2100 are not. This rule matters when checking February’s length or counting weekdays across February.
Why do some months take up six calendar rows?
The number of rows depends on both the month’s length and its starting weekday. A 31-day month needs six rows if it starts on Friday or Saturday; a 30-day month needs six if it starts on Saturday. At the other extreme, a 28-day February starting on Sunday fits exactly into four rows.
How many Saturdays and Sundays are in a month?
Every month has at least four Saturdays and four Sundays. A fifth Saturday or Sunday depends on where the extra days fall after four complete weeks. To check, count the dates in each weekend column; a month can have eight, nine, or ten weekend days in total.
How can I read the calendar as a Monday-first calendar?
Treat Monday as the first column and Sunday as the last, then move each date to its corresponding weekday column. The dates and their weekdays do not change—only their positions in the grid do. For a Monday-first printout, use a calendar tool with a configurable week start; this generator’s layout cannot be switched.
Does this calendar show ISO week numbers?
No. ISO weeks begin on Monday, and ISO week 1 is the week containing January 4. Because an ISO week can span two months or even two years, its number cannot be inferred just by counting rows in this Sunday-first calendar. Use an ISO week-number calendar if you need week numbers for scheduling.
Can I use this calendar to check historical dates?
Use caution with historical dates. JavaScript date calculations follow Gregorian-style rules even for periods or places that used a different calendar, such as the Julian calendar. Calendar reforms also skipped dates in some countries. In addition, this tool may interpret entered years 1–99 incorrectly; consult a historical calendar source for those dates.
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