Convert a Date to The Creator's Calendar

Enter a Gregorian, Hijri or any other date to see it in The Creator's Calendar — lunar months kept in their seasons — with the moon number within its season.

How does conversion work?

How to use

  • Choose the calendar your date is written in, then type the day, pick the month and type the year; the result appears instantly, no button needed.
  • If you change the calendar after entering a valid date, the same day is converted into the new calendar instead of keeping the numbers.
  • Months of The Creator's Calendar are listed by name, with Al-Nasi always last because its position changes and it does not occur every year; choosing it in a year without Al-Nasi shows a message saying so.
  • The supported range is 1 January, year 1 to 15 February 3001 (Gregorian). No calendar has a year zero: the year before 1 is −1.

Reading the results

  • The five calendar cards always appear in the same order: The Creator's Calendar, Solar Hijri, Gregorian, Julian, Lunar Hijri; the card of the calendar you entered is outlined. Each card's copy button copies its date.
  • Under The Creator's Calendar date: the moon number within its season (moon 1, 2, 3 or 4 of spring…); under Solar Hijri the month number; under Julian its offset from Gregorian (13 days between 1900 and 2100).
  • "Open this day" shows the whole day on the Today page with its timings, moon and events. The page address in your browser carries the entered date, so copying and sending it opens the calculator on the same date.

Day details

  • First row: the weekday; the ISO week — weeks start on Monday and week 1 is the one containing the year's first Thursday, so early-January days may belong to the last week of the previous year (1 January 2027 is in week 53 of 2026); and the Julian Day Number — a continuous day count used by astronomers, related to the Julian calendar in name only.
  • Second row: the day's position in the year of each calendar and the days left.
  • Third row: the type and length of each year:
    • Gregorian: a leap year every 4 years, except century years unless divisible by 400 (1900 common, 2000 leap).
    • Julian: a leap year every 4 years, without exception.
    • Solar Hijri: the year starts at the astronomical Nowruz, so it has 365 or 366 days depending on the equinox.
    • Lunar Hijri: 354 or 355 days depending on the actual month lengths; 355 counts as a leap year.
    • The Creator's Calendar: a common year of 12 months (354–355 days), or a leap year of 13 months with Al-Nasi (383–385 days), which keeps the months in their seasons.

Example

Sunday 18 October 2026 Gregorian = 7 Ramadan 1404 in The Creator's Calendar = 26 Mehr 1405 Solar Hijri = 5 October 2026 Julian = 7 Jumada al-Ula 1448 Lunar Hijri; it is day 291 of the Gregorian year, ISO week 42, Julian Day Number 2461332.

Notes

  • Before 15 October 1582 European dates were written in the Julian calendar; when copying a date from an old source, choose "Julian" as the input calendar.
  • Lunar Hijri and The Creator's Calendar here are astronomical, using the Madinah reference, so the Hijri date may differ by a day from Umm al-Qura or from the official sighting in your country.
How is the duration calculated?

How to use

  • Enter one date under "From" and another under "To", each in any calendar (the start can be Hijri and the end Gregorian).
  • Order does not matter: if the second date is before the first, the duration is shown as absolute with a notice.

Including the end date

  • By default the days between the dates are counted (like nights): 1 January to 31 January = 30 days.
  • Tick "Include end date" to count both days (as for a vacation or a course): the same span becomes 31 days.

Reading the results

  • The number of days in large type, with weeks and remaining days.
  • Then one card per calendar in the standard order: the duration in that calendar in years, months and days, its total of whole months (once it reaches a year), and the start and end dates in it.
  • In the solar calendars (Gregorian, Julian, Solar Hijri) the largest number of whole months is counted, then the remaining days. A whole month runs from a day number to the same number; if that day does not exist in the target month, its last day is used: 31 January to 29 February 2024 = one month.
  • In Lunar Hijri, real lunar months are counted (29 or 30 days each, by the new moons), 12 months to a year. In The Creator's Calendar, its whole years (12 or 13 months) are counted, then its lunar months; its months are the same lunar months, so the total matches Hijri.
  • That is why results can differ slightly between calendars for the same number of days: month lengths differ from one calendar to another.
  • Tropical years: the days divided by the tropical year (365.2422 days).
  • Working days: tick "Working days" and pick the weekend (Friday & Saturday, Saturday & Sunday, Friday, Sunday); only weekend days are excluded, not public holidays.

Examples

From 8 April 2024 to 18 October 2026 = 923 days (131 weeks and 6 days): Gregorian 2 years, 6 months and 10 days (30 months in total), Lunar Hijri 2 years, 7 months and 8 days (31 lunar months in total), The Creator's Calendar 2 years, 7 months and 8 days; 2.53 tropical years.

Working days in October 2026 (1 October to 1 November) with a Friday & Saturday weekend = 21 days out of 31.

To calculate your age up to today, use the Age tab: it works in every calendar and shows your next birthday.

How are addition and subtraction calculated?

How to use

  • Enter the base date in any calendar, choose Add or Subtract, then the amount and the unit (days, weeks, months, years).
  • For months or years, choose "Count months and years in": the calendar to count in, since a "month" in the Gregorian calendar is not a "month" in the Hijri one. The result is shown in all five calendars.

Days and weeks

An exact day count, independent of the calendar: 18 October 2026 + 100 days = 26 January 2027.

Solar months and years (Gregorian, Julian, Solar Hijri)

  • The month is added in that calendar keeping the day number. If that day does not exist in the resulting month, its last day is used:
    • 31 January 2024 + 1 month = 29 February 2024 (28 February in a common year).
    • 31 March + 1 month = 30 April.
    • 29 February 2024 + 1 year = 28 February 2025.
  • So subtracting may not bring you back: 31 January 2024 + 1 month = 29 February, then − 1 month = 29 January, because days 30 and 31 were lost when the month end was used.

Lunar months (Lunar Hijri and The Creator's Calendar)

  • A month here is a real lunar month, by the new moons (29 or 30 days), not a fixed number of days: you move to the next month and keep the day number. 7 Jumada al-Ula 1448 + 1 month = 7 Jumada al-Akhirah 1448, whatever the length of Jumada al-Ula.
  • If the day is 30 and the resulting month has 29 days, the result is day 29.
  • A Hijri year = 12 lunar months: 7 Jumada al-Ula 1448 + 1 year = 7 Jumada al-Ula 1449.
  • The months of The Creator's Calendar are the same lunar months (same boundaries as Hijri), so adding a month in it moves you to its next month, and Al-Nasi counts as a month.

Years of The Creator's Calendar

  • A year has 12 or 13 months, so a year is not a fixed number of months; instead you move to the same month by name in the target year: 7 Ramadan 1404 + 1 year = 7 Ramadan 1405.
  • Al-Nasi is counted by its month number, not its name, because it does not occur every year and its position changes: 3 Al-Nasi 1404 (the 5th month) + 1 year = 3 Jumada al-Ula 1405, since 1405 has no Al-Nasi and its 5th month is Jumada al-Ula. If Al-Nasi was the 13th month and the target year has 12 months, the result falls in the 12th month.
How is age calculated?

How to use

  • Enter your date of birth in the calendar you know; the age is calculated up to today in the time zone of the city selected on the site.
  • For the span between any two other dates, use the Duration tab.

Reading the results

  • At the top: the total days you have lived and the weekday you were born on.
  • Then one card per calendar, in the standard order: your age in it (years, months, days), your date of birth in it, and your next birthday in it with the days left.

Why does the age differ between calendars?

  • A lunar year (354–355 days) is about 11 days shorter than a solar year, so the Hijri age gains a full year roughly every 33 solar years.
  • Years of The Creator's Calendar follow the solar year on average thanks to Al-Nasi, so the age in it is close to the Gregorian age; its remaining months are counted as real lunar months.
  • The Julian age usually equals the Gregorian age, but the birthday falls on the Julian date (2 March Julian = 15 March Gregorian today).

Birthdays in special cases

  • Born on 29 February: the birthday in a common year is 28 February. Likewise day 30 of a lunar month that has 29 days, or 30 Esfand in a common Solar Hijri year: the month's last day is used.
  • The Creator's Calendar: the birthday is in the same month by name every year — except for those born in Al-Nasi, whose birthday follows the month number: born in Al-Nasi as the 5th month means a birthday in the 5th month every year, whether or not it is Al-Nasi (3 Al-Nasi 1404 → 3 Jumada al-Ula 1405).

Example

Born 15 March 1990, calculated on 18 October 2026: 36 years, 7 months and 3 days Gregorian, 37 years, 8 months and 19 days Hijri, and 36 years, 7 months and 19 days in The Creator's Calendar; 13,366 days lived in total, and the next Hijri birthday is 18 Sha'ban 1448 (in 100 days).

A calendar of the sun and the moon

The Creator's Calendar joins the precision of the solar year with the real lunar cycle: the day begins at true dawn, the month begins with the new moon (by the conjunction and the moon's age), and the year is made of four astronomical seasons bounded by the equinoxes and solstices. Each month keeps its season, as its name indicates: the two Rabi' months in spring and Ramadan in autumn.

Twelve lunar months fall about 11 days short of the solar year, so in a year with 13 new moons a thirteenth month, Al-Nasi, is added to the season that gathered four moons, bringing the months back into their seasons.

How it differs from the Lunar Hijri calendar

Lunar HijriThe Creator's Calendar
Months in a yearAlways 1212, and 13 in a leap year (Al-Nasi)
Length of the year354–355 days354–355 days; a leap year 383–385
The seasonsIts months drift through them, a full cycle in about 33 yearsFixed: the two Rabi' months in spring, Ramadan in autumn
Events of the Prophet's eraTheir weekdays do not matchTheir weekdays match

Both share the same month boundaries, so the month name and year number differ between them on the same day.

The witness of history

The sources give the weekday of the best-known events of the Prophet's era, and these weekdays fall exactly in The Creator's Calendar:

EventDateThe Creator's CalendarLunar Hijri
The Hijra12 Rabi' al-Awwal, year 1MondayThursday
The Battle of Badr17 Ramadan, year 2FridayMonday
The Prophet's death12 Rabi' al-Awwal, year 11MondaySaturday

The events from the Prophet's birth to al-Hasan ibn Ali's handover of rule to Muawiya in year 41 agree with The Creator's Calendar, and the events after it agree with the Lunar Hijri calendar — at that juncture the calendar was replaced. Follow the 73 events with their sources on the Historical Events page, read more on the About the Calendar page, or browse a whole month on the Monthly Calendar.

Frequently asked questions

What is The Creator's Calendar?

A lunisolar calendar: its months are real lunar months starting from the conjunction and the moon's age, and its year is solar, with the months kept in their seasons by adding a thirteenth month, Al-Nasi. Each month stays in its season as its name indicates — the two Rabi' months in spring and Ramadan in autumn — and the day begins at dawn. It is the calendar the Arabs dated by before the Hijra, and it remained in use in Madinah in the Prophet's time and after him until al-Hasan ibn Ali handed rule to Muawiya.

What is the difference between The Creator's Calendar and the Lunar Hijri calendar?

Both use the same lunar months, but the Lunar Hijri calendar always has twelve months (354 or 355 days), so it moves about 11 days earlier every year and Ramadan passes through all the seasons in about 33 years. The Creator's Calendar adds Al-Nasi in a year with 13 new moons, so its months stay in their seasons. That is why the month name and year number differ between the two on the same day, and why the weekdays of events from the Prophet's era match The Creator's Calendar, not the Lunar Hijri calendar.

What is Al-Nasi?

A thirteenth month added in a year with 13 new moons, in the season that gathered four moons, to bring the months back into their seasons, since twelve lunar months fall about 11 days short of the solar year. A common year has 12 months (354 or 355 days), a leap year 13 months (383 to 385 days).

What is the evidence that The Creator's Calendar was in use in the Prophet's time?

The weekdays that the sources give for the best-known events: the day of the Hijra, Monday 12 Rabi' al-Awwal of year 1; the day of Badr, Friday 17 Ramadan of year 2; and the Prophet's death, Monday 12 Rabi' al-Awwal of year 11. All fall on these weekdays in The Creator's Calendar, while in the Lunar Hijri calendar they fall on Thursday, Monday and Saturday. The Historical Events page lists 73 events with their sources, from the Prophet's birth to the handover of rule to Muawiya, that attest to this.

How do I convert a date to The Creator's Calendar?

Enter the date in any calendar; its equivalent appears on The Creator's Calendar card with the moon number within its season. Example: 18 October 2026 = 7 Ramadan 1404, the first moon of autumn.