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How many weeks are in a year?
A year has 52 weeks and 1 day: 365 days divided by 7. A leap year has 52 weeks and 2 days. Week numbers are different: 2026 has 53 ISO weeks and 2027 has 52, because the count depends on the weekday the year starts.
By Asier Fernández ·
Weeks in each year
| Year | Days | Weeks | Starts on | ISO week numbers |
|---|---|---|---|---|
| 2025 | 365 | 52 weeks + 1 day | Wednesday | 52 |
| 2026 | 365 | 52 weeks + 1 day | Thursday | 53 |
| 2027 | 365 | 52 weeks + 1 day | Friday | 52 |
| 2028 | 366 | 52 weeks + 2 days | Saturday | 52 |
| 2029 | 365 | 52 weeks + 1 day | Monday | 52 |
| 2030 | 365 | 52 weeks + 1 day | Tuesday | 52 |
Why some years have 53 week numbers
The ISO 8601 standard, used by most calendars and payroll systems outside the US and by many plants, numbers weeks from Monday to Sunday. Week 1 is the week that contains the first Thursday of the year, so a year has 53 numbered weeks when it starts on a Thursday, or on a Wednesday in a leap year. 2026 starts on a Thursday, so it has week 53, which runs from December 28, 2026 to January 3, 2027.
US calendars often count weeks differently, starting on Sunday with January 1 always in week 1. Check which system your employer's schedule or payroll uses before you match week numbers.
Weeks and paychecks
52 weeks means 26 biweekly paychecks in most years. The extra day each year adds up, and every 11 years or so a biweekly payroll has 27 paydays in a calendar year. In 2027 there are 53 Fridays, so payrolls paid every other Friday starting on January 1, 2027 get 27 paychecks. The 2027 pay period calendar lists them.
Work weeks and hours
At 40 hours a week, 52 weeks is 2,080 work hours. Taking out two weeks of vacation leaves 50 working weeks and 2,000 hours. For the exact weekday count of each year and the hours of rotating shift schedules, see work hours in a year.
More guides
Figures are worked out from each cycle; rules checked against official sources on . How we calculate
Questions
How many weeks are in a year?
52 weeks and 1 day (365 days), or 52 weeks and 2 days in a leap year (366 days).
Does 2026 have 53 weeks?
It has 53 ISO week numbers, because it starts on a Thursday. Week 53 runs from Monday, December 28, 2026 to Sunday, January 3, 2027. In days, 2026 has 52 weeks and 1 day like any normal year.
How many weeks are in 2027?
52 ISO weeks. 2027 starts on a Friday and has 365 days.
What week of the year is it?
Use the calculator above: it gives the ISO week number of any date. ISO weeks start on Monday and week 1 contains the first Thursday of the year.
How many work weeks are in a year?
52, or 50 if you take two weeks of vacation. At 40 hours a week, 52 weeks is 2,080 hours.