Home   Calendar   The Islamic Leap Year

The Islamic Leap Year

As an observational lunar calendar, the traditional Islamic Hijri calendar does not have leap years. However, some countries and Muslim communities use a rule-based version with leap years called the Tabular Islamic calendar.


The Muslim pilgrimage to Mecca in Hajj.

The Muslim pilgrimage to Mecca occurs during the month of Dhu 'l-Hidjdja, which is one day longer in leap years.


No Leap Years

Months in the traditional version of the Islamic calendar are directly tied to the timing of the Moon phases. The length of each month is determined by the duration of a Moon cycle or lunation, specifically the time from one Waxing Crescent Moon to the next.

Even though the sum of 12 lunar months consistently falls 11 days short of the length of a solar year, Islamic time reckoning does not employ correction mechanisms, like leap days in the Gregorian calendar.

Read more about the traditional Hijri calendar

Unpredictable Months

As in Jewish time reckoning, a new month in the Islamic calendar traditionally begins after the New Moon, when a thin Crescent Moon becomes visible just after sunset. However, in contrast to the Hebrew system, the Islamic calendar relies on an actual observation of the Crescent Moon. This makes the timing of the months difficult to predict. For example, bad weather conditions may delay the beginning of a new month by 1 day at very short notice.

The Tabular Islamic Calendar

To make Islamic time reckoning more predictable and less dependent on lunar observations, Muslim scholars developed the Tabular Islamic calendar in the 8th century CE. This system uses arithmetical rules to determine the length of each month and inserts leap days on a regular basis.

Like in the traditional version, each year has 12 months. However, their length is predetermined: months with uneven numbers have 30 days, while months with even numbers have 29 days.

In a leap year, a day is added to the 12th and final month, Dhu 'l-Hidjdja, making it 30 days long. Common years in the Tabular Islamic calendar have 354 days, while leap years are 355 days long.

Leap Years Rules

A leap day is added every 2 to 3 years. There are 11 leap years in a 30-year cycle. Their distribution varies slightly from one country or Muslim community to another. However, the most common version defines the 2nd, 5th, 7th, 10th, 13th, 16th, 18th, 21st, 24th, 26th, and 29th year of each 30-year cycle as leap years.

In Step with the Lunar Year

Inserting a leap day on a regular basis keeps the Tabular Islamic calendar in sync with the lunar year, which is a little longer than 354 days.

In contrast to the leap days inserted in solar calendars like the Gregorian calendar and the leap months used in lunisolar systems like the Jewish calendar, the Islamic leap day is not designed to adjust the calendar with the solar year, which on average lasts just over 365 days.

Pilgrimage Month

Dhu 'l-Hidjdja is 1 of the 4 sacred months in the Hijri calendar. It is the month of the Hajj – the Muslim pilgrimage to Makkah. The other sacred months are Rajab, Dhū al-Qa‘dah, and Muḥarram.

Topics: Leap Year, Calendar

Create Calendar With Holidays


Alternative Leap Years

  1. Bahá'í Calendar Leap Year
  2. Chinese Calendar Leap Year
  3. Ethiopian Calendar Leap Year
  4. Hindu Calendar Leap Year
  5. Persian Calendar Leap Year
  6. Islamic Calendar Leap Year
  7. Jewish Calendar Leap Year
  8. Buddhist Calendar Leap Year

Leap Years in Other Calendars

You might also like

Is There a Perfect Calendar?

Our calendar does not accurately reflect the length of a tropical year, the time it takes Earth to complete a full orbit around the Sun. Why is that so and are there other calendars that do a better job? more

The exterior of Ras Makkonen Selassie church in Harar, Ethiopia.

The Ethiopian Calendar

The Ethiopian calendar is quite similar to the Julian calendar, which was the predecessor to the Gregorian calendar most countries use today. more

February 30

February 30 actually existed at least twice in the past, according to historical records. more