Calendar Generator – Build a Printable Monthly or Yearly Calendar
A calendar is one of the most frequently needed reference tools, yet opening a spreadsheet or design program just to lay out a grid of dates is overkill for most tasks. The Calendar Generator builds an accurate Gregorian calendar for any year from 1 to 9999 directly in your browser. Choose a single month or a full 12-month overview, customize which weekday the grid starts on, and mark important dates with your own labels — all without installing anything or uploading data anywhere.
How the Calendar Is Built
The tool computes the weekday of the first day of a month using new Date(year, month - 1, 1).getDay() and the number of days in that month with new Date(year, month, 0).getDate(). Leading days from the previous month and trailing days from the next month are added automatically so every row is a complete seven-day week, matching how printed calendars are traditionally laid out.
Choosing a Week Start Day
Different regions expect the calendar week to start on different days. The United States, Canada, and several other countries typically start the week on Sunday, while the ISO 8601 standard and most of Europe start on Monday. Some workplace schedules use Saturday as the first day instead. Switching the Week Start Day option instantly reorders the columns without changing any of the underlying dates.
Highlighting Holidays, Birthdays, and Deadlines
Use the Highlight Dates field to mark any day that matters to you. Enter one date per line (or separate them with commas) in the format YYYY-MM-DD, optionally followed by a short label, such as 2026-12-25, Christmas Day. Matching days appear as a colored badge on the grid, and hovering shows the label you provided. Highlighted dates that fall within the selected month are also listed separately beneath the calendar for quick reference.
ISO Week Numbers and Leap Years
Toggle Show week numbers to display the ISO 8601 week number beside each row, calculated using the standard rule that week 1 contains the year's first Thursday. This is useful for payroll cycles, academic terms, and project planning that track progress by week rather than by date. The tool also automatically detects leap years using the Gregorian rule — divisible by 4, except century years that are not divisible by 400 — and reports whether February has 28 or 29 days.
Full-Year Overview and Printable Layouts
Switch to the Full Year tab to see all 12 months as a compact grid, ideal for annual planning or printing a one-page wall calendar. Enabling Include notes column in Month view adds a blank column beside each week for handwritten reminders when printing a single month as a planner insert.