Free Calendar Week Calculator
Planning by the week starts with knowing exactly where a date sits. Enter any date and instantly see its complete Monday-to-Sunday calendar week, with the ISO week number and the full date range - everything you need for scheduling, reporting and week-based planning in one view.
How to Use the Calendar Week Calculator
- Pick a date (or leave it as today).
- Click Show Calendar Week to see all seven days.
- Use the week number and date range for planning.
Features
The tool renders all seven days of the week containing your chosen date, highlighting the selected day so you can orient yourself at a glance. It also shows the ISO 8601 week number and the week’s exact date range, and it defaults to today so you can check the current week with a single click.
Benefits & Use Cases
Managers planning sprints and rotas, payroll teams aligning weekly pay periods, and teachers mapping out lesson weeks all work in week numbers - this gives them the full picture instantly. It is also handy whenever someone references "week 32" and you need to know which dates that actually means.
Tips
Weeks follow the ISO standard and start on Monday, which matches most business calendars. Need just the number without the full week view? The Week Number Calculator gives you the ISO week plus the ISO year and weekday. The selected day is highlighted in the grid, so pick any date to reorient the view.
Frequently Asked Questions
What is a calendar week?
The seven-day block - Monday to Sunday - that contains your chosen date. This tool displays every day in that block with the selected date highlighted.
Which week-numbering standard is used?
ISO 8601, the international standard: weeks start on Monday, and week 1 is the week containing the first Thursday of the year.
What is an ISO week number?
A number from 1 to 53 identifying the week within its ISO year. It is widely used in business planning, manufacturing and European payroll.
Can I look up a week for a future or past date?
Yes. Pick any date - past, present or future - and the tool shows the calendar week it falls in.
Why does my phone show a different week number?
Some calendars start weeks on Sunday or use different week-1 rules, especially in the US. ISO 8601 (Monday start) is the business standard in most of the world.
Do I need an account to use it?
No. It is free, runs entirely in your browser, and requires no sign-up.
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