Week Number
Look up the ISO week number for today or any date, and see the weeks of the year.
Current ISO week
—
- ISO week number
- —
Quick answer
Today, Wednesday, November 4, 2026, is in ISO week 45 of 2026 (UTC). Week numbers here follow ISO 8601: weeks start on Monday and week 1 is the week containing the year's first Thursday, so most years have 52 weeks and some have 53.
- Read the Current ISO week at the top.
- Use Look up any date to find another date's week.
Reviewed by the TimerHub team · Last reviewed November 4, 2026 · Data sources
Related tools
- CalendarA clean monthly and yearly calendar with week numbers and quick navigation.
- Date CalculatorAdd or subtract days, weeks, months, and years from any date to find a new date.
- Days Between DatesCalculate the exact duration between two dates in days, weeks, months, and business days.
- Age CalculatorFind your exact age in years, months, days and hours, plus your life in numbers: heartbeats, full moons and laps around the sun.
- Dog Age CalculatorConvert dog years to human years by size, with a cat age calculator and a full chart.
- Due Date CalculatorEstimate your pregnancy due date, how many weeks along you are, and your trimester dates from your last period.
How to use it
- 1
Check the current week
The large number shows today's ISO week, along with the week year and date.
- 2
Pick any date
Use the date field to look up the ISO week number for a past or future date.
- 3
Read the result
See the ISO week number and the week-numbering year for the date you chose.
Perfect for every need
Business & operations
Reference the ISO week for sprints, reporting, payroll, and production schedules.
- Sprint labels
- Weekly reports
- Payroll weeks
Manufacturing & logistics
Match week-based date codes used on products, batches, and shipping schedules.
- Production week codes
- Batch tracking
- Delivery planning
Planning & scheduling
Coordinate teams across regions using a shared, unambiguous week number.
- Team calendars
- Academic weeks
- Event planning
Frequently asked questions
How does ISO week numbering work?
Under ISO 8601, weeks start on Monday and week 1 is the week containing the year's first Thursday. This is the standard used across Europe and in business worldwide.
Why can a January date be in week 52 or 53?
Early January days can belong to the last week of the previous year. That is why the tool also shows the week-numbering year, which can differ from the calendar year.
How many ISO weeks are in a year?
Most years have 52 weeks, but some have 53. It depends on which weekday the year starts on and whether it is a leap year.
Is the current week number live?
Yes. The current week updates automatically based on your device clock, so it stays correct across midnight and year boundaries.