Welcome to WeekNumbers.net

Ever seen a calendar that says "Week 42" and wondered what that means? You're in the right place.

What Are Week Numbers?

Week numbers are a system used to number the weeks in a year — typically from Week 1 to Week 52 (and sometimes Week 53). They’re especially common in Europe and international business settings, making scheduling easier across languages and time zones.

The most widely used system is the ISO 8601 week date standard, where:

• The week starts on a Monday
• Week 1 is the week containing the first Thursday of the year
• There are usually 52 weeks, but some years have 53

Why Use Week Numbers?

Week numbers are used globally in a wide range of industries:

• Software Development – agile sprints, release planning
• Manufacturing – production timelines, delivery schedules
• Education – academic semesters and exams
• Project Management – task tracking and coordination

What You Can Do on This Site

• 📅 Look up week numbers for any year
• 🔢 Understand how ISO weeks are calculated
• 📆 Get the week number of any specific date
• 🔄 Switch between years instantly with URL parameters

Chek week numbers for 2026:

Fun Fact

Did you know? Week 1 in ISO format can actually start in the *previous calendar year*! For example, Week 1 of 2025 begins on Monday, December 30, 2024.

Start Exploring

List the week numbers of the coming years.

• 2026
• 2027
• 2028
• 2029
• 2030
• 2031
• 2032
• 2033
• 2034
• 2035
• 2036
• 2037
• 2038
• 2039
• 2040
• 2041
• 2042
• 2043
• 2044
• 2045
• 2046
• 2047
• 2048
• 2049
• 2050
• 2051
• 2052
• 2053
• 2054