One calendar, several ways of reckoning
All Muslims share the same Hijri calendar of twelve lunar months, from Muharram to Dhu al-Hijjah, counted from the Hijrah. What differs between communities is how the start of each month is determined: by sighting the new crescent, by astronomical calculation, or by a fixed arithmetic table. These differences can put the same date on different days.
OIOA’s Islamic Home screen offers Shia, Bohra (Dawoodi, Misri) and Makkah (Umm al-Qura) options, so families can follow the reckoning they use. This page explains the background respectfully and in general terms. For rulings, please follow your own scholars.
The Bohra tabular calendar
The Dawoodi Bohra community, whose roots lie in the Fatimid tradition of Egypt and later Yemen, follows a tabular calendar. Rather than waiting for the crescent each month, the months follow a fixed arithmetic pattern that was worked out in the Fatimid period. That pattern is often called the Misri (Egyptian) reckoning, after its origin in Fatimid Cairo.
In a typical tabular scheme:
- months alternate between 30 and 29 days, starting with a 30-day Muharram,
- the last month, Dhu al-Hijjah, has 29 days in a common year and 30 in a leap year,
- a 30-year cycle contains 11 leap years.
This keeps the average month very close to the true lunar month over the long run, and lets the community know every date, including the start of Ramadan and the Eids, well in advance.
Because a tabular calendar doesn’t depend on sighting, Bohra dates for Ramadan and Eid often fall a day or so before dates announced by sighting-based committees. Both are faithful to their own tradition.
The Bohra options in OIOA are labelled Dawoodi and Misri, so that families can choose the reckoning their community follows. If you’re unsure which to choose, please ask your local jamaat.
Shia reckoning
Shia communities, including Twelver Shia (Ithna Ashari) communities in India, generally begin months by sighting the new crescent, following the guidance of their marja’ (religious authority) and local scholars. Authorities differ on questions such as whether a sighting in another region is accepted, and whether optical aids or calculations may establish visibility. So Shia communities may begin a month on a different day from Sunni communities in the same place, or from each other.
Important dates in the Shia calendar include Muharram, and in particular Ashura on 10 Muharram, observed as a time of mourning for Imam Husayn and the martyrs of Karbala; Arba’een, forty days later; and the birth and martyrdom anniversaries of the Imams.
Why OIOA offers options instead of one calendar
There’s no single “correct” Islamic calendar that every Muslim in India follows. A Sunni family, a Shia family and a Bohra family in the same building may start Ramadan on different days, each faithfully following their tradition. An app that showed only one date would be wrong for many of its users. So OIOA lets you choose.
Practical tips
- Choose the option your community follows on the Islamic Home screen.
- For sighting-based communities, treat OIOA’s date as the expected date and follow your local announcement.
- For Bohra families, the tabular calendar gives dates in advance; your jamaat’s calendar is the authority.
- When neighbours observe a different day, it’s a difference of reckoning, not of faith.
In OIOA
The Islamic Home screen shows the Islamic calendar in the option you choose, with prayer times, Jumma and Qibla, calculated on your phone and available offline. If an option doesn’t match your community’s calendar, please tell us what we missed.
Common questions
Why do Bohras celebrate Eid before other communities?
Because the Bohra calendar is tabular: its months follow a fixed arithmetic cycle rather than sighting, and that cycle often places the start of a month a day or so before the crescent is sighted in India.
What does ‘Misri’ mean?
Misri means “Egyptian”. It refers to the reckoning that traces back to the Fatimid period in Egypt.
Do Shia and Sunni communities always differ?
No. Often they begin a month on the same day. Differences arise when sighting reports are borderline and authorities assess them differently.
Is Ashura on the same day for everyone?
Ashura is 10 Muharram, so its Gregorian date depends on when Muharram began in the calendar a community follows. Usually communities in the same region agree, but they can differ by a day.
Can I see the Hijri date in more than one calendar?
OIOA lets you switch the calendar option at any time, so you can see how the date compares across the options it offers.
Key terms
- Tabular calendar: an arithmetic calendar with fixed month lengths and a leap-year cycle.
- Marja’: a senior religious authority whom Shia Muslims follow.
- Jamaat: a local community, in the Bohra context the local congregation.
- Ashura: the 10th day of Muharram.
A shared calendar, with respect
The twelve months, the sacred months, Ramadan, the Eids and Muharram are shared by all Muslims. Differences in reckoning are about method, and each method is held sincerely. OIOA’s aim is simply to show each family the calendar it follows, accurately.
Does OIOA decide which calendar option is correct?
No. It offers options and leaves the choice to you and your community’s scholars.
Muharram and Ashura across communities
The month of Muharram holds a special place for Shia Muslims, who mourn the martyrdom of Imam Husayn at Karbala with majlis gatherings and processions, culminating on Ashura, the 10th. Sunni Muslims also regard Ashura as significant, and many fast on that day. Dawoodi Bohras observe the first ten days of Muharram with sermons and remembrance. In many Indian cities, people of every community are familiar with the processions and gatherings of Muharram, and government holiday lists include it. Because each community’s calendar may start Muharram on a slightly different day, Ashura can also differ by a day between communities. OIOA’s calendar options let each family see the date in the reckoning it follows.