Calendar Week Grid
Render a month grid with ISO week numbers.
Overview
The Calendar Week Grid renders any month as a Monday-start table with ISO 8601 week numbers down the left edge, the weekday header across the top, and the days of the month laid out in their correct columns. Pick a year and month and you get a printable mini-calendar that matches the layout used by European school timetables, project Gantt charts, and most enterprise scheduling apps.
Useful for project managers planning sprints by week number, freelancers who invoice on ISO weeks, anyone localising a UI for a Monday-first audience, and teams that need a quick visual of where a holiday or release falls within the quarter.
How it works
The grid uses the ISO 8601 week-numbering rules: weeks run Monday through Sunday, and week 1 is the week containing the first Thursday of the year (equivalently, the week containing January 4). That means early-January dates can belong to week 52 or 53 of the previous year, and late-December dates can roll into week 1 of the next.
Each cell is computed from the proleptic Gregorian calendar, and the renderer pads the leading and trailing edges with the previous and next month's days greyed out so the grid is always a clean six-by-seven block.
Examples
January 2026
Wk Mon Tue Wed Thu Fri Sat Sun
01 1 2 3 4
02 5 6 7 8 9 10 11
03 12 13 14 15 16 17 18
December 2024 → Dec 30 falls in ISO week 01 of 2025
January 2027 → Jan 1 falls in ISO week 53 of 2026
FAQ
Why does my January 1 show week 53?
When January 1 is a Friday, Saturday, or Sunday, it belongs to the last ISO week of the prior year. Week 1 starts on the following Monday, which contains the first Thursday of January.
Can I switch to a Sunday-first layout?
The grid is fixed to the ISO Monday-first convention since that is what the week numbers refer to. A Sunday-first view would misalign the week-number column.
Are there 53-week years?
Yes — years where January 1 is a Thursday, or leap years where it is a Wednesday, contain 53 ISO weeks. There are roughly 71 such years per 400-year cycle.
Does it handle non-Gregorian calendars?
No, the grid is Gregorian only. For Hebrew, Hijri, or Persian dates, use the alternate-calendar converter and read the day-of-week from there.
Why is the previous month's tail shown faintly?
The padded days keep the grid rectangular and make it easy to see which weekday the first of the month lands on without counting blank cells.