Week Number Calculator
Find the week number for any date. Essential for business planning, project management, and ISO 8601 date formatting.
Understanding Week Numbers
Week numbers provide a standardized way to reference specific weeks within a year. The ISO 8601 standard defines Week 1 as the week containing January 4th, making week numbering consistent worldwide.
Businesses use week numbers for reporting periods, project timelines, and fiscal year planning. Many countries in Europe and Asia commonly reference dates by week number rather than month.
A year can have 52 or 53 weeks depending on which day of the week January 1st falls on and whether it's a leap year.
How to Use This Calculator
- Enter any date
- Click "Find Week Number"
- See the week number and day of the week
- Use for business planning and scheduling!