How Many Weeks Are in a Year? (Easy Answer + 2025 Guide) Updated 2025
Short answer: 52 weeks + 1 day (common year) or 52 weeks + 2 days (leap year). Some calendars show an ISO week 53 depending on how the year starts/ends.
The Simple Math
- Common year: 365 ÷ 7 = 52 weeks + 1 day.
- Leap year: 366 ÷ 7 = 52 weeks + 2 days.
Takeaway: The extra 1–2 days are why some weekdays happen 53 times in a year.
What Is ISO Week 53?
ISO weeks start on Monday. “Week 1” is the week containing the year’s first Thursday. Depending on how the dates align, some years include a week numbered 53.
Helpful Links
- Month lengths: Days in Each Month
- See weekend totals: Weekends in a Year
- Estimate workdays: Working Days
- Convert to hours/minutes/seconds: Conversions
Frequently Asked Questions
Is 2025 a leap year?
No—2025 has 52 weeks + 1 day.
Can two years in a row have ISO week 53?
Yes, depending on how the calendar lines up at year boundaries.