How many weeks are in a year?

The short answer: a year has 52 weeks and 1 extra day, and a leap year has 52 weeks and 2 extra days. But if you count numbered weeks, the way planners, payroll and project schedules do, some years have 53 — and 2026 is one of them. Here is where the 53rd week comes from, plus weeks in a month, at work and in a school year.

52 weeks and a day or two

Those spare days mean one or two weekdays occur 53 times a year. 2026 starts on a Thursday and ends on a Thursday, so it has 53 Thursdays and 52 of every other day. If you are paid weekly on Thursdays, that is 53 paydays this year instead of the usual 52.

Why 2026 has 53 weeks

The international standard for week numbers, ISO 8601, is used across Europe and by many businesses and software tools worldwide. Its rules:

• weeks run Monday through Sunday;
• week 1 is the week that contains the year’s first Thursday;
• each week belongs entirely to the year its Thursday falls in.

That gives 52 or 53 numbered weeks. A year gets 53 when it starts on a Thursday, or when it is a leap year that starts on a Wednesday. 2026 started on a Thursday, so it has 53 ISO weeks: week 1 runs from December 29, 2025 to January 4, 2026, and week 53 from December 28, 2026 to January 3, 2027.

In Excel and Google Sheets, =ISOWEEKNUM(A1) gives the ISO week of the date in A1. The plain =WEEKNUM(A1) uses the common US convention instead: weeks start on Sunday and week 1 is whichever week contains January 1. Because the first and last weeks are usually partial, December 31 lands in week 53 most years — and in 2028, a leap year that starts on a Saturday, in week 54.

How many weeks are in a month

On average a month is 4.35 weeks (365 days ÷ 12 ÷ 7). More precisely:

A quarter is about 13 weeks (90–92 days) and half a year about 26.

Work weeks and work hours in a year

A full-time job is usually figured as 52 weeks × 40 hours = 2,080 hours a year — the number used to turn an annual salary into an hourly rate and back. Actual working weeks are fewer: take away paid time off and holidays (the US has 11 federal holidays, though private employers choose which ones they observe), and most people work roughly 48–50 weeks a year.

To count working days between two dates, =NETWORKDAYS(A1,B1,holidays) skips weekends and any holidays you list — more in how to count the days between two dates.

How many weeks are in a school year

Most US states require around 180 school days, which at five days a week is about 36 weeks of school. On the calendar the year stretches from late August or early September to late May or June — closer to 40 weeks — because of breaks and holidays. A college semester is typically about 15–16 weeks including finals. Exact dates come from your district’s or school’s calendar.

Count the weeks to something

Weeks are handy for longer stretches: weeks until a trip, a due date or graduation, or weeks since you moved. In Temfy: Countdown Days & Widget countdowns and count-ups run in days, hours, minutes and seconds, a Home Screen widget shows what is coming up, and a reminder arrives at the moment of the event or ahead of it — an hour, a day or a week before. Free for iPhone and Android.