How Many Days in a Year?
A standard year has 365 days, while a leap year has 366 days. But the number of business days, weekdays, and weekends varies from year to year depending on how the calendar falls. This guide breaks down all the numbers you need, explains why Earth's orbit creates the need for leap years, and covers how different calendar systems handle the year length differently.
- Regular year: 365 days
- Leap year: 366 days (every 4 years, with exceptions)
- Business days: ~251-252 per year
- Weekdays: 261-262 per year
- Weeks: 52 weeks + 1 day (or +2 in leap years)
Days Per Year Breakdown
Here is how the days in a year break down by type:
| Type | Regular Year | Leap Year |
|---|---|---|
| Total Days | 365 | 366 |
| Weeks | 52.14 | 52.29 |
| Weekend Days | 104 | 104-106 |
| Weekdays | 261 | 260-262 |
| Business Days* | ~251 | ~251-252 |
| Hours | 8,760 | 8,784 |
| Minutes | 525,600 | 527,040 |
| Seconds | 31,536,000 | 31,622,400 |
*After excluding ~10-11 federal holidays
Days Per Year: 2020-2030
The exact number of weekend days, weekdays, and business days varies each year based on which day of the week January 1 falls on and how holidays align with the calendar. Here is a comprehensive table:
| Year | Leap? | Total Days | Weekend Days | Weekdays | Business Days |
|---|---|---|---|---|---|
| 2020 | Yes | 366 | 104 | 262 | 252 |
| 2021 | No | 365 | 104 | 261 | 251 |
| 2022 | No | 365 | 105 | 260 | 250 |
| 2023 | No | 365 | 105 | 260 | 250 |
| 2024 | Yes | 366 | 104 | 262 | 252 |
| 2025 | No | 365 | 104 | 261 | 251 |
| 2026 | No | 365 | 104 | 261 | 251 |
| 2027 | No | 365 | 104 | 261 | 251 |
| 2028 | Yes | 366 | 106 | 260 | 250 |
| 2029 | No | 365 | 104 | 261 | 251 |
| 2030 | No | 365 | 104 | 261 | 251 |
Business day counts are based on US federal holiday schedules. The exact count may differ by 1-2 days depending on holiday observation rules in a given year.
Why Is a Year 365.25 Days?
A year is defined by how long it takes Earth to complete one full orbit around the Sun. According to NASA, this takes approximately 365.2422 days (365 days, 5 hours, 48 minutes, and 46 seconds). This is called a tropical year or solar year.
Because the actual orbital period is not a whole number, our calendar needs a correction mechanism. Without it, the calendar would drift by about 1 day every 4 years, or roughly 24 days every century. Eventually, summer would shift into what the calendar calls winter.
The solution is the leap year system: by adding an extra day every 4 years, the average calendar year becomes 365.25 days. The Gregorian calendar further refines this to 365.2425 days by skipping leap years in certain century years, which is extremely close to the actual 365.2422-day orbital period.
The remaining error is only about 1 day every 3,236 years — accurate enough for all practical purposes. For authoritative time standards, see the National Institute of Standards and Technology (NIST) time and frequency division.
Different Calendar Systems
Not all civilizations use the same calendar. Here is how major calendar systems handle the year length:
| Calendar | Year Length | Leap Year Rule | Used By |
|---|---|---|---|
| Gregorian | 365 / 366 days | Every 4 years (skip most centuries) | Most of the world |
| Julian | 365 / 366 days | Every 4 years (no exceptions) | Some Eastern Orthodox churches |
| Islamic (Hijri) | 354 / 355 days | 11 leap years in a 30-year cycle | Muslim-majority countries |
| Hebrew | 353-385 days | 7 leap months in a 19-year cycle | Israel, Jewish communities |
| Chinese | 353-385 days | Leap month every ~3 years | China, East Asia (traditional) |
| Persian (Solar Hijri) | 365 / 366 days | Complex 2820-year cycle | Iran, Afghanistan |
The Islamic calendar is notably shorter because it is purely lunar (based on the Moon's phases). This means Islamic holidays shift about 10-12 days earlier each Gregorian year. The Hebrew and Chinese calendars are lunisolar, adding an extra month periodically to stay aligned with the seasons.
Business Days Per Year
For work planning and payroll, business days matter more than calendar days. In the United States, business days are weekdays (Monday through Friday) minus federal holidays. The typical formula is:
For 2026: 365 - 104 - 10 = 251 business days.
Key facts about business days per year:
- The typical range is 250-252 business days
- Leap years may add one business day if Feb 29 falls on a weekday
- The US has 11 federal holidays, but some fall on weekends
- Private employers may observe different holidays
For detailed monthly breakdowns and industry variations, see our business days per year guide. Use our business days calculator to count working days between any two dates.
Days Per Month Quick Reference
The 365 (or 366) days in a year are distributed across 12 months of varying lengths. For a detailed breakdown, see our days in each month guide.
| Month | Days | Month | Days |
|---|---|---|---|
| January | 31 | July | 31 |
| February | 28 / 29 | August | 31 |
| March | 31 | September | 30 |
| April | 30 | October | 31 |
| May | 31 | November | 30 |
| June | 30 | December | 31 |
Seven months have 31 days, four have 30 days, and February has 28 days (29 in a leap year). The total is (7 x 31) + (4 x 30) + 28 = 365 days in a regular year.
Astronomical vs. Calendar Year
It is worth distinguishing between different types of "year" used in science and everyday life:
| Type of Year | Length (Days) | Definition |
|---|---|---|
| Calendar year | 365 or 366 | Jan 1 to Dec 31 (Gregorian calendar) |
| Tropical year | 365.2422 | Time for Earth to return to the same equinox position |
| Sidereal year | 365.2564 | Time for Earth to complete one orbit relative to the stars |
| Anomalistic year | 365.2596 | Time between successive perihelion passages |
| Fiscal year | 365 or 366 | 12-month period used for financial reporting (varies by organization) |
| Academic year | ~270-290 | School calendar, typically September to June |
The Gregorian calendar is calibrated to the tropical year, which is what determines the seasons. The small difference between the tropical year (365.2422 days) and the Gregorian average (365.2425 days) means our calendar will be off by about one day after 3,236 years.
How Year Length Affects Date Calculations
The length of a year matters whenever you calculate dates that span multiple months or years. Here are common scenarios:
- Adding 365 days vs. adding 1 year: Adding 365 days to a date in a leap year may land one day short of the same date next year
- Age calculations: Your exact age in days depends on how many leap years you have lived through. Use our days alive calculator to find out
- Contract deadlines: "One year from today" legally means the same calendar date next year, not 365 days later
- Interest calculations: Financial institutions may use a 360-day year (12 months of 30 days) for simplicity, or the actual day count
For calculations involving specific dates, our date calculator and add days tool automatically handle leap years and varying month lengths.
Frequently Asked Questions
A standard (non-leap) year has 365 days. This breaks down to 52 weeks and 1 day. The 12 months range from 28 to 31 days each.
A leap year has 366 days. The extra day, February 29, is added to keep the calendar aligned with Earth's orbital period. Leap years occur every 4 years, except for most century years. See our leap year guide for the complete rules.
Approximately 251 business days in a typical year in the United States, after excluding 104 weekend days and about 10 federal holidays that fall on weekdays. The exact count varies by 1-2 days each year. See our detailed breakdown.
There are 261 weekdays (Monday through Friday) in a typical 365-day year. This is different from business days, which further excludes holidays. In a leap year, there may be 260-262 weekdays depending on which days of the week the year starts and ends on.
The next leap year is 2028. The most recent leap year was 2024. After 2028, the following leap years will be 2032, 2036, and 2040. For the complete list, see our leap year guide.
Earth's orbital period around the Sun is approximately 365.2422 days. Since we cannot have a fractional day in the calendar, we use 365 days as the base and add an extra day every 4 years (leap year) to compensate. The Gregorian calendar's leap year rules bring the average to 365.2425 days per year, which is very close to the true orbital period.