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Calendar and Date Converter: Hijri, Gregorian, Shamsi, Hebrew, Chinese, Maya

Convert a date between 13 calendars: Gregorian, Hijri (Umm al-Qura and tabular), Solar Hijri (Shamsi), Hebrew, Chinese, Indian, Buddhist, Julian, Coptic, Ethiopian, ancient Egyptian and Maya.

Enter the values to see the result here.

Formula

Every conversion goes through one shared count of days, the Julian Day Number (JDN). A date in calendar A is turned into a JDN, then that JDN is turned into a date in calendar B, so any pair of calendars works. For the Gregorian calendar, with a=⌊(14−m)/12⌋a = \lfloor (14 - m)/12 \rfloor, y′=y+4800−ay' = y + 4800 - a and m′=m+12a−3m' = m + 12a - 3:

JDN=d+⌊153m′+25⌋+365y′+⌊y′4⌋−⌊y′100⌋+⌊y′400⌋−32045\text{JDN} = d + \left\lfloor \frac{153m' + 2}{5} \right\rfloor + 365y' + \left\lfloor \frac{y'}{4} \right\rfloor - \left\lfloor \frac{y'}{100} \right\rfloor + \left\lfloor \frac{y'}{400} \right\rfloor - 32045

The Julian calendar drops the century terms and subtracts 32083. The Coptic, Ethiopian, tabular Hijri and Egyptian civil calendars are fixed arithmetic cycles from a known first day, and the Hebrew calendar uses the molad rules with their postponements. Umm al-Qura, Solar Hijri, Indian and Chinese dates come from the browser’s calendar data.

For the Maya Long Count, with N=JDN−584283N = \text{JDN} - 584283 days since 0.0.0.0.0:

baktun=⌊N144000⌋,katun=⌊N7200⌋ mod 20,tun=⌊N360⌋ mod 20\text{baktun} = \left\lfloor \frac{N}{144000} \right\rfloor,\quad \text{katun} = \left\lfloor \frac{N}{7200} \right\rfloor \bmod 20,\quad \text{tun} = \left\lfloor \frac{N}{360} \right\rfloor \bmod 20

and the uinal is ⌊N/20⌋ mod 18\lfloor N/20 \rfloor \bmod 18 and the kin is N mod 20N \bmod 20. The 260-day Tzolk’in count is ((N+3) mod 13)+1((N + 3) \bmod 13) + 1 with a name from a list of 20, and the 365-day Haab’ position is (N+348) mod 365(N + 348) \bmod 365.

Worked example

Convert Wednesday 20 March 2024 (Gregorian) to the other calendars.

  • With m=3m = 3: a=0a = 0, y′=6824y' = 6824, m′=0m' = 0. Then JDN=20+0+2,490,760+1,706−68+17−32,045=2,460,390\text{JDN} = 20 + 0 + 2{,}490{,}760 + 1{,}706 - 68 + 17 - 32{,}045 = 2{,}460{,}390.
  • Hijri (Umm al-Qura): 10 Ramadan 1445. Solar Hijri: 1 Farvardin 1403, the Persian new year.
  • Hebrew: 10 Adar II 5784, a leap year. Chinese: day 11 of month 2 of 2024, the Wood Dragon year.
  • Coptic: 11 Paremhat 1740. Ethiopian: 11 Megabit 2016. Indian national: 30 Phalguna 1945. Buddhist: 20 March 2567. Julian: 7 March 2024.

A Maya check: 21 December 2012 has JDN 2,456,283, so N=2,456,283−584,283=1,872,000=13×144,000N = 2{,}456{,}283 - 584{,}283 = 1{,}872{,}000 = 13 \times 144{,}000. That is 13.0.0.0.0, written 4 Ahau 3 Kankin in the two short cycles.

Common mistakes

  • Expecting a lunar day to start at midnight. Hijri and Hebrew days begin at sunset, so an evening can already belong to the next calendar date.
  • Treating one Hijri source as the only truth. Umm al-Qura, the tabular calendar and local moon sighting can each differ by a day.
  • Typing the Chinese lunar year number instead of the Gregorian year in which that lunar year starts, or forgetting to tick the leap month box.
  • Forgetting there is no year 0 in everyday BCE dating. Here year 0 means 1 BCE and -1 means 2 BCE for the Gregorian and Julian calendars.
  • Using the Coptic calendar when you want the ancient Egyptian civil year, or the reverse. They share month names but not leap days.

Frequently asked questions

Which calendars can I convert between, and in which direction?

Any of the 13 to any other: Gregorian, Hijri (Umm al-Qura and tabular civil), Solar Hijri (Shamsi), Hebrew, Chinese, Indian national, Buddhist, Julian, Coptic, Ethiopian, ancient Egyptian civil and the Maya Long Count. Pick the calendar you have in the first list and the one you want in the second; the table underneath shows the same day in all of them.

Why can a Hijri date differ by a day from another website or my local announcement?

Umm al-Qura is calculated in advance, the tabular civil calendar follows a fixed 30-year cycle, and many countries start a month only after the crescent is sighted locally. These can disagree by one or two days, so use this tool for planning and your local authority for religious dates.

What is the leap month box for, and why is the Chinese calendar limited to 1600 to 2200?

The Chinese calendar is lunisolar and adds a leap month in about seven years of every nineteen, which repeats a month number, so you tick the box to say which of the two you mean. The month and year boundaries come from astronomical calculation in the browser, which is dependable for 1900 to 2100 and only approximate outside it.

Is the ancient Egyptian civil calendar the same as the Coptic calendar?

No. The ancient civil year had 12 months of 30 days plus 5 extra days and never added a leap day, so it slid against the seasons by one day every four years. The Coptic calendar inherits the month names but adds a leap day every fourth year, which keeps it aligned with the Julian calendar.

How reliable is the Maya Long Count conversion?

The Long Count is exact once you fix a correlation, and this tool uses the common GMT value of 584283, which puts 13.0.0.0.0 on 21 December 2012. Some scholars prefer 584285, which would move every result by two days, so check the source if a published date matters.

Why does the Hebrew calendar have Adar I and Adar II?

To keep the lunar months in step with the seasons, seven years in every nineteen are leap years with a thirteenth month. In those years Adar is doubled into Adar I and Adar II, and the dropdown only accepts the months that exist in the year you typed.

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