Weekly Calendar

How week numbers work

This calendar numbers weeks with the ISO 8601 standard, which is what most diaries, business planners, payroll systems and spreadsheets use. Under ISO rules, every week runs from Monday to Sunday, and week 1 is the week that contains the first Thursday of January. That rule keeps every week whole: a week is never split between two years. It also means the first few days of January can belong to week 52 or 53 of the previous year, and the last days of December can already be week 1 of the next.

If you use the Sunday first view, the dates move to a Sunday-to-Saturday layout, as in most US and Canadian wall calendars, but the week number shown is still the ISO number of the Monday in that week, so it matches your planner and your spreadsheet's ISOWEEKNUM function. To check any single date, use the week number tool.

Week numbers and dates

Every ISO week of 2026 and 2027 with its Monday and Sunday. Select a week to open it in the calendar above.

More calendar views

Zoom out to the monthly calendar or the yearly calendar, check tomorrow's date, or count down with days until. For a printable weekly planner with space for notes, visit weeklycalendar.in, part of the same network.