https://www.weeknumber.cc/ Free online week number calculator. Instantly see what week it is. ISO 8601 & US systems. Free JSON API. 18,000+ pages, 15 languages. en Fri, 20 Jun 2026 12:00:00 +0800 https://www.weeknumber.cc/countdown.html Real-time countdown to the next week. See exactly how many days, hours, minutes, and seconds until the next week starts. Share with friends! Fri, 20 Jun 2026 12:00:00 +0800 https://www.weeknumber.cc/countdown.html https://www.weeknumber.cc/compare.html Compare two dates and see how many weeks apart they are. Perfect for project management, pregnancy tracking, and semester planning. Fri, 20 Jun 2026 12:00:00 +0800 https://www.weeknumber.cc/compare.html https://www.weeknumber.cc/birth-week.html Enter your birth date and discover which week of the year you were born. Learn fun facts about your birth week! Fri, 20 Jun 2026 12:00:00 +0800 https://www.weeknumber.cc/birth-week.html https://www.weeknumber.cc/life-in-weeks.html See your entire life in weeks. Inspired by Wait But Why, this interactive tool shows how many weeks you've lived and how many remain. Fri, 20 Jun 2026 12:00:00 +0800 https://www.weeknumber.cc/life-in-weeks.html https://www.weeknumber.cc/week-quiz.html 10 questions to test your week number knowledge. How well do you know ISO 8601 and week calculations? Fri, 20 Jun 2026 12:00:00 +0800 https://www.weeknumber.cc/week-quiz.html https://www.weeknumber.cc/api/week Free REST API for week number calculations. No API key required. CORS enabled. Get current week, date-to-week conversion, and week date ranges. Fri, 20 Jun 2026 12:00:00 +0800 https://www.weeknumber.cc/api/week https://www.weeknumber.cc/widget.html Add a free week number widget to any website with one line of code. Supports 15 languages. No API key needed. Fri, 20 Jun 2026 12:00:00 +0800 https://www.weeknumber.cc/widget.html https://www.weeknumber.cc/ WeekNumber.cc now supports 15 languages: Chinese, English, Japanese, Korean, Spanish, French, German, Portuguese, Russian, Arabic, Hindi, Thai, Vietnamese, Indonesian, and Turkish. Fri, 20 Jun 2026 12:00:00 +0800 https://www.weeknumber.cc/ https://www.weeknumber.cc/history/2026/25/ Discover what happened in each week of years past. 583 history pages covering major events from 2015 to 2025. Fri, 20 Jun 2026 12:00:00 +0800 https://www.weeknumber.cc/history/2026/25/ https://www.weeknumber.cc/blog/why-2026-has-53-weeks.html 2026 is a 53-week year under ISO 8601. Learn why some years have 53 weeks and what it means for payroll, planning, and more. Fri, 20 Jun 2026 12:00:00 +0800 https://www.weeknumber.cc/blog/why-2026-has-53-weeks.html