Week Number Calculator - ISO Week Numbers & Calculations
Calculate week numbers according to ISO 8601 standard, find weeks between dates, and convert between week numbers and dates. Perfect for business planning and scheduling.
52
Week 52 of 2024 (December 23 - December 29)
Find Week Number for Date
Calculate Weeks Between Dates
Convert Week Number to Date
2024
About ISO 8601 Week Numbers
ISO 8601 Standard
Week numbers follow the ISO 8601 international standard where weeks start on Monday and the first week contains January 4th.
Week Numbering
Most years have 52 weeks, but some years have 53 weeks. Week 1 is the first week with at least 4 days in the new year.
Business Use
Week numbers are commonly used in business for planning, scheduling, and reporting across different countries and industries.
International Standard
ISO 8601 is recognized worldwide and ensures consistent week numbering across different systems and countries.
How to Use the Week Number Calculator
Find Week Number
Enter any date to find its corresponding ISO week number, including week year, start/end dates, and day of week information.
Calculate Weeks Between
Calculate the exact number of weeks between two dates, including full weeks, remaining days, and working weeks.
Week to Date Conversion
Convert week numbers back to date ranges. Enter a year and week number to see the corresponding Monday-Sunday date range.
Week Calendar View
Browse through years to see all week numbers in a visual calendar format. Click on weeks to see detailed information.