- How many days are in a year?
- A regular year has 365 days. A leap year has 366 days. The average year is 365.25 days, which is why we add a leap day every 4 years.
- How many weeks are in a year?
- A regular year has 52 weeks and 1 day. A leap year has 52 weeks and 2 days. Some years have 53 ISO calendar weeks when January 1 falls on a Thursday.
- How many days are in each month?
- January: 31 · February: 28 (29 in a leap year) · March: 31 · April: 30 · May: 31 · June: 30 · July: 31 · August: 31 · September: 30 · October: 31 · November: 30 · December: 31
- What is a leap year?
- A leap year is a year divisible by 4 — except for century years, which must be divisible by 400. So 2000 was a leap year, but 1900 was not. The next leap year after 2024 is 2028.
- What is the ISO week number?
- The ISO week number is a standard (ISO 8601) that numbers the weeks of the year from 1 to 52 or 53. Week 1 is defined as the week containing the first Thursday of the year. Monday is the first day of the ISO week.
Calendar Questions
Age Calculation Questions
- How do I calculate my age?
- Subtract your birth year from the current year. If your birthday has not yet occurred this year, subtract 1. Example: born in 1990, current year 2026, birthday not yet passed → age = 35.
- How old is someone born in 1990?
- Someone born in 1990 is 35 or 36 years old in 2026, depending on whether their birthday has passed.
- How old is someone born in 2000?
- Someone born in 2000 is 25 or 26 years old in 2026, depending on whether their birthday has passed.
- What is the difference between age calculator and chronological age calculator?
- An age calculator computes how old you are from your date of birth to today. A chronological age calculator does the same, but is specifically used in medical or educational contexts to measure the precise time elapsed (often in years, months, and days) for developmental assessments.
Days & Business Days Questions
- What is the difference between calendar days and business days?
- Calendar days count all 7 days of the week. Business days (also called working days) count only Monday through Friday, excluding public holidays. A 5-business-day deadline from Monday is Friday; a 5-calendar-day deadline from Monday is Saturday.
- How many business days are in a month?
- Most months have 20–23 business days, depending on the month and how many weekends it contains. February has the fewest (18–20), months with 31 days starting on Monday or Tuesday have the most (23).
- How many days until Christmas?
- Christmas is December 25. The number of days depends on today's date — use the countdown calculator on this site for an exact count.
Time Zone Questions
- What is UTC?
- UTC (Coordinated Universal Time) is the world's primary time standard. It does not observe daylight saving time. All other time zones are expressed as offsets from UTC (e.g., UTC+1, UTC−5).
- What is the difference between GMT and UTC?
- For everyday purposes, GMT and UTC are the same. GMT (Greenwich Mean Time) is a time zone; UTC is a time standard. They share the same current time, but UTC is the precise scientific standard used for official timekeeping.
- How many time zones are there?
- There are 38 standard UTC offsets, ranging from UTC−12:00 to UTC+14:00. Some countries span multiple time zones — Russia has 11, the USA has 6 (excluding territories), and France has 12 (including overseas territories).
FAQ
How many days are in a year?
A regular year has 365 days. A leap year has 366 days. The calendar averages 365.25 days per year, which is corrected by adding a leap day (February 29) every 4 years.
How many weeks are in a year?
A regular year has 52 weeks and 1 extra day. A leap year has 52 weeks and 2 extra days. In ISO week numbering, some years have 53 complete weeks.
What is the current week number?
The current ISO week number changes every Monday. Use the week number calculator on this site to see today's week number for any year.
How do I convert days to months?
Divide the number of days by 30.44 (the average days per month) for an approximate result. For an exact conversion, use a date calculator that accounts for the actual length of each month.