Calendar Tools and Date Calculators
15 free date calculators and calendar reference pages: find today's week number or day of the year, count the days between two dates, convert Julian dates, and look up leap years, Friday the 13th, daylight saving time and the first day of each season.
Updated · By the YearlyCalendar.org team
Today at a glance
Thursday, November 5, 2026today
45ISO week number
309day of the year
56days left this year
Date calculators
What Week Is It? Current Week NumberToday's ISO 8601 week number and the dates of every weekDay of the Year CalendarToday's day number and a day-of-year chart for 2026Days Between Dates CalculatorCount days, weeks, months and business days between two datesJulian Date ConverterConvert dates to Julian Day Numbers and YYDDD ordinal dates
Calendar reference
Leap Years ListThe leap year rule, every leap year 1800–2400 and the next leap dayPerpetual Calendar & Repeating YearsThe 14 possible calendars and the years that share themFriday the 13th DatesThe next Friday the 13th and every one from 2020 to 2040Months of the YearThe 12 months in order with days, seasons and name originsDays of the WeekWeekday order, ISO numbers and where the names come fromFiscal Year Dates by CountryFiscal year start and end dates for the US and other countries
Seasons and clock changes
Daylight Saving Time DatesNext US clock change: March 14, 2027 (DST begins)First Day of SpringSpring 2027 begins March 20 (March equinox)First Day of SummerSummer 2027 begins June 21 (June solstice)First Day of FallFall 2027 begins September 23 (September equinox)First Day of WinterWinter 2026 begins December 21 (December solstice)