Calculation for Crescent
A Reliable Method to Meet the Objective of Shari’ah
By Dr. Muzammil H. Siddiqi

هُوَ الَّذِي جَعَلَ الشَّمْسَ ضِيَاء وَالْقَمَرَ نُورًا وَقَدَّرَهُ مَنَازِلَ لِتَعْلَمُواْ عَدَدَ السِّنِينَ وَالْحِسَابَ مَا خَلَقَ اللّهُ ذَلِكَ إِلاَّ بِالْحَقِّ يُفَصِّلُ الآيَاتِ لِقَوْمٍ يَعْلَمُونَ {يونس 5}

It is He Who made the Sun to be a shining glory and the Moon to be a light (of beauty), and measured out stages for her; that you might know the number of years and the count (of time). Nowise did Allah create this but in truth and righteousness. (Thus) does He explain His Signs in detail, for those who understand. (Yunus 10:5)

الشَّمْسُ وَالْقَمَرُ بِحُسْبَانٍ {الرحمن 5}

The Sun and the Moon follow courses (exactly) computed. (Al-Rahman 55:5)

Text Box: On Jumada al-‘Ula 14, 1427, A.H. (June 10, 2006 A.D.), the Fiqh Council of North America approved the use of astronomical calculations in determining the beginning and end of the Islamic lunar months. The birth of the new Moon, followed by a calculated amount of movement of the new Moon above the horizon, will be used to determine when the Crescent Moon will become sightable. Sightability of the Crescent anywhere in the world, as opposed to actual reports of local physical Crescent sightings, will determine the beginning and end of each new lunar month. Based on this methodology, Islamic lunar calendars can be prepared in advance without uncertainty.

In order to understand Fiqh Council’s decision, let us understand the following points:

      1.      Allah subhanahu wa ta’ala has created the Sun and Moon and both of them move according to precise and pre-defined patterns. Knowledge of these patterns help people calculate time, days and years, as mentioned in Surah Yunus, ayah 5.  This pattern is not only for Ramadan, but it is for all time periods throughout the year. 

      2.      Allah subhanahu wa ta’ala tells us that we should pray our daily Salat and begin and end our fasts based on the movement of the sun.

أَقِمِ الصَّلاَةَ لِدُلُوكِ الشَّمْسِ إِلَى غَسَقِ اللَّيْلِ وَقُرْآنَ الْفَجْرِ إِنَّ قُرْآنَ الْفَجْرِ كَانَ مَشْهُودًا {الإسراء 78)

Establish regular prayers -with the sun's decline till the darkness of the night, and the morning prayer and reading: for the prayer and reading in the morning carry their testimony. (Al-Isra’ 17:78)

....وَكُلُواْ وَاشْرَبُواْ حَتَّى يَتَبَيَّنَ لَكُمُ الْخَيْطُ الأَبْيَضُ مِنَ الْخَيْطِ الأَسْوَدِ مِنَ الْفَجْرِ ثُمَّ أَتِمُّواْ الصِّيَامَ إِلَى الَّليْل….   (البقرة 187)

…. and eat and drink, until the white thread of dawn appear to you distinct from its black thread; then complete your fast Till the night appears…. (Al-Baqarah 2:187)

Allah also told us that we should establish the months of Ramadan and Hajj by the Crescent Moons. He says,

يَسْأَلُونَكَ عَنِ الأهِلَّةِ قُلْ هِيَ مَوَاقِيتُ لِلنَّاسِ وَالْحَجِّ (البقرة 189)

They ask thee concerning the New Moons. Say: They are but signs to mark fixed periods of time in (the affairs of) men, and for Pilgrimage.(Al-Baqarah 2:187)

3. The Prophet –peace be upon him- in explaining these rules told us how to observe the movements of the sun to establish the timings of daily Salat and the beginning and ending of the daily fasts. Similarly he told us how to begin and end the month of Ramadan.

4. For centuries Muslims observed the movement of the sun according to the Sunnah. They observed the movement of the sun by their naked eyes every day for their five daily prayers. When clocks were invented, Muslims changed this method and started used calculated movements of the sun.  They did so even though there are no Ayah or Hadith that provide for using calculated time or timetables for Salat.  They established the timings of daily Salat and developed perpetual Salat timetables that can be used throughout the year. Now, instead of physically watching movements of the sun, we can follow a timetable that is based on the calculations of the movements of the sun. Timetables sometime differ on the basis of the Fiqh of prayer times. Some Muslims have determined that Fajr should start when the sun is 18 degree below the horizon; others have determined that Fajr time should start when the sun is 15 degree below the horizon. Some calculate Maghrib time when the sun disk descends the horizon and others calculate Maghrib time at when the red twilight disappears. Similar are the differences in the beginning and ending times of fasts. However, no one disputes the use of calculated time itself and preparing timetables Salat as bid’ah (innovations) or forbidden in Islam.

5. The Prophet –peace be upon him- told us that we should see the Crescent to begin and end the month of Ramadan. He said,

سَمِعْتُ أَبَا هُرَيْرَةَ رَضِيَ اللَّهُ عَنْهُ يَقُولُ قَالَ النَّبِيُّ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ أَوْ قَالَ قَالَ أَبُو الْقَاسِمِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ صُومُوا لِرُؤْيَتِهِ وَأَفْطِرُوا لِرُؤْيَتِهِ فَإِنْ غُبِّيَ عَلَيْكُمْ فَأَكْمِلُوا عِدَّةَ شَعْبَانَ ثَلَاثِينَ  (البخارى 1776)

“Fast with sighting it (Moon) and break the fast with sighting it. Complete 30 days of Sha’aban if it is cloudy.” (Al-Bukhari 1776)

            He –peace be upon him- also said,

عَنْ نَافِعٍ عَنْ عَبْدِ اللَّهِ بْنِ عُمَرَ رَضِيَ اللَّهُ عَنْهُمَا أَنَّ رَسُولَ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ ذَكَرَ رَمَضَانَ فَقَالَ لَا تَصُومُوا حَتَّى تَرَوْا الْهِلَالَ وَلَا تُفْطِرُوا حَتَّى تَرَوْهُ فَإِنْ غُمَّ عَلَيْكُمْ فَاقْدُرُوا لَهُ (البخارى 1773)

“Do not fast until you see the Crescent and do not break the fast until you see it. Estimate about it in case it is cloudy.” (Al-Bukhari 1773)

6. The Prophet –peace be upon him- wanted that Muslims should make sure that the month has begun before they start their ‘Ibadah of fasting so that they be united in their observance of this act of worship together. He also told us that we should make sure that this month has ended so that we may have our celebration of Eid together.

7. The Prophet –peace be upon him- also said in this context:

حَدَّثَنَا سَعِيدُ بْنُ عَمْرٍو أَنَّهُ سَمِعَ ابْنَ عُمَرَ رَضِيَ اللَّهُ عَنْهُمَا عَنْ النَّبِيِّ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ أَنَّهُ قَالَ إِنَّا أُمَّةٌ أُمِّيَّةٌ لَا نَكْتُبُ وَلَا نَحْسُبُ الشَّهْرُ هَكَذَا وَهَكَذَا يَعْنِي مَرَّةً تِسْعَةً وَعِشْرِينَ وَمَرَّةً ثَلَاثِينَ

(البخارى 1780)

“We are an unlettered people; we do not know how to write and how to calculate. The month is thus and thus, meaning either 29 days or 30 days.” (Al-Bukhari 1780) 

The Prophet –peace be upon him- was fully aware of the condition of his people at that time and he gave them the instructions according to their capacity. He gave them a method that was easy and simple so that they could start and end their ‘Ibadah with confidence that it is in the month of Ramadan.

8.      Muslims in general continued sighting the Crescent to begin and end their month of Ramadan and celebrate Eid. It is reported that among the great Tabi’in Mutarrif ibn Shikkhir held the opinion that calculations of Crescent can be used for Ramadan. Imam Taqiuddin al-Subki a great Shafi’i jurist even said that calculation were more reliable that eye sighting. When Muslims learned writing and calculations and became more knowledgeable about the Moon and its various phases, more voices were raised to rely on the calculations of the Crescent instead of its physical sighting. Most jurists did not accept calculations because they were not sure whether the calculations were correct or could be trusted. With the development of astronomical sciences in the last one hundred years more and more voices are being raised by jurists in support of calculations. One of the famous Muhaddith Shaikh Ahmad Muhammad Shakir wrote a long article emphasizing that calculation is the most appropriate method of determining the lunar months and it is permissible.

9.      The objective of the Shari’ah is that Muslims begin and end the month of Ramadan with assurance and be united in the observance of these blessed times. The objective of the Shari’ah is not that Muslims merely conduct Moon sightings or remain uncertain about their time of ‘Ibadah until the last minute. The astronomical sciences are highly advanced today and more reliable methods are available to know the beginning of the lunar months. On the basis of the principles of the Shari’ah just as the timetable for Salat and Siyam are prepared, it is possible to prepare the calendars for the lunar months and for the beginning and end of Ramadan. This knowledge is now easily available and can be used.   

10.  The Fiqh Council of North America has given us a method that fulfills the basic requirement of the Shari’ah.  This method is based on two principles:

a.       The new Moon is born. This means that the conjunction must have taken place.

b.      The new Moon has become the Hilal. Enough time has passed to make this Moon sightable.

By scientific calculations we know very accurately and definitely when the conjunction has taken place and the new Moon is on the way to become Hilal. It becomes Hilal when it is above the Horizon and has moved to certain degrees of altitude to receive the light of the sun. By scientific knowledge we then know that the Hilal has appeared and it is sightable. Whether people see it or not depends on many factors. Actual sighting is, however, not required when we know definitely that the Crescent is there.

11.  Sighting of the Crescent has generated a lot of controversies and divisions in the Ummah today. In Muslim countries the official bodies make the decision. Some people differ but they have no choice except to follow the official decision. Countries where Muslim minorities live there is more division. In Western Europe and North America Moon sighting has become a much more divisive issue.

12.  The new method of the Fiqh Council is based on the principles of the Shari’ah. It complies with the Sunnah of our beloved Prophet –peace be upon him- and it uses our growing and advanced scientific astronomical knowledge. By accepting this method we can unite ourselves and can take the benefit of knowing our important dates in advance. This is an important benefit and it will save us many difficulties that we and our young people go through every year during Ramadan and Eid.

We pray to Allah to keep us on the right path and help us to keep our minds open for ideas that are consistent with new knowledge without contradicting the basic principles of our deen. Amin.


There are some frequently asked questions (FAQ). Following are the brief answers:

Q1. What about the Qur’anic ayah that says,

فَمَن شَهِدَ مِنكُمُ الشَّهْرَ فَلْيَصُمْهُ  (لابقرة 185)

So every one of you who is present (at his home) during that month should spend it in fasting (Al-Baqarah 2:185)

            Does it not mean that one must see the Crescent?

A1.  The word “shahida” does not always mean “to see.” It has four different meaning. It means:            

a)      to see

b)      to be present

c)      to know

d)     to testify and announce

We cannot translate this ayah to mean “Whosoever see the month must fast,” because month is time and time cannot be seen. Secondly if Allah would have said that “whosoever see the Crescent must fast,” then fasting would be obligatory on only those who see the Moon. Most of the commentators of the Qur’an have taken it mean “to be present (residing at home, not traveling) during the month.

Q2.      The Prophet –peace be upon him- said “Fast with its sighting…” and in another Hadith he is reported to have said that “Do not fast until you see it.”  So how can you say that seeing the Crescent is not required?

A2.      The same expression are used in the Qur’an for daily prayers “Establish regular prayers with the declining of the sun till the darkness of night…”(17:78) but we do not observe the decline of the sun or the darkness of the night. We rather use our watches. The same expression is also used for starting and ending our fast when Allah said, “Eat and drink until the white thread is clear from the black thread and complete your fast until the night” (2:187), but we use nowadays our watches to start and end our fasts.  This shows that a mechanism can be used to calculate the movement of the sun. If this can be done for the sun, why cannot it be done for the Moon?  Allah told us that both of them move according to set patterns and both of them are made to learn counting and to make calendar. 

Q 3.     By using calculation, you are going against the “majority of the Jurists (jumhur al-fuqaha)”.

A 2.     Jumhur did not forbid the calculation because calculation in this matter was forbidden according to the Shari’ah. They forbade it because they believed that it was not a reliable method. They did not trust the astronomers and some of them thought that they use the same methods of superstition and conjectures that astrologers use.  We know that this is not the case and astronomical science is now highly developed.

Q 4.     Is this not a bid’ah i.e. innovation in religion?

A 4.     No, this is not a “bid’ah.”  The definition of “bid’ah” isالإحداث في الدين “introducing something new in religion.” It is not  الإحداث للدين  “introducing something new for the sake of religion.”  We are not adding anything new in Islam; we are only using new knowledge to observe the rules of the Shari’ah. It is like using loudspeakers for the Salat. When loudspeakers came and people wanted to use them, some people also objected that it was “bid’ah”; but now they are used universally.

Q 5.     Is this not against the Sunnah?

A 5.     It would have been against the Sunnah if we said that we should use solar calendar instead of lunar calendar or mix the solar and lunar calendars. It would have been against the Sunnah if we said that Ramadan should be in winter only or during summer holidays. We are strictly following the Sunnah; actually we can say that by using calculations we are using a more accurate method of following the Sunnah.

Q 6.     Are you not dividing the Ummah by introducing this method?

A 6.     People are divided because they cannot agree on one method of sighting the Crescent and there are always disputes about who saw it and where and how many witnesses there were, etc. This scientific method is intended  to help people become more objective and accurate and, Insha’Allah, this will unite the Ummah.

Q 7.     Watching the Moon is easy; calculations are difficult and you are making the Ummah dependant on the astronomers.

A 7.     It is more difficult for people nowadays to watch for the Crescent. Most people prefer to know about it by making a telephone call or checking through the internet.  Easy and difficult are relative terms. Things that were easy are now difficult and things that were difficult at one time are now easy. In the old days it was easy to go out and check the sunrise and sunset for your daily prayers but now using the watches and timetables is easier. No one will argue that we have made people dependent on watches nor will anyone argue that assembling a watch is easy.  But watches are easily available. Similarly, it is very easy to find out today about the phases of the Moon through your daily news papers or checking through the internet. Those who live in areas where these facilities are not available they can use what is easier for them.

Q 8.     The Prophet –peace be upon him- told us that we should make a du’a after sighting the Crescent, now how can we say our du’a?

A 8.     According to scholars Hilal is not necessarily the Crescent of the first night. Some say that first seven nights of the month are the nights of Hilal. So whenever you see the Crescent you make the du’a.  Du’a is also recommended. If you did not make du’a by sighting the Crescent, your fast is still valid. Du’a is recommended for every month when you see the Crescent, not only for the month of Ramadan.

Q 9.     Why are you doing this now, why didn’t you do it 50 years ago?

A 9.     We have been discussing this for a long time. I have been working for the Moon sighting committee for the past 30 years and most of the time saw Muslims in America divided on this subject.  We also now have the benefit of many years of empirical evidence using the advanced scientific astronomical knowledge which we are now adopting.  This empirical evidence has shown on numerous occasions the accurate birth and sightability of the Moon.  If you have followed Moon sighting reports in the past, you may be  aware of circumstances where Muslim communities have followed physical Moon sighting reports that were later found to be incorrect, and circumstances where it was later determined that the Crescent was present even though no Moon sighting reports came forward.  The scientifically calculated methodology has been proven through experience to avoid these mistakes.  Moreover, we had to find a solution that can unite us and help us to move forward Insha’Allah. May Allah help us.

Q 10.  Are you “liberal” Muslims?  Is this a special madhhab that you are creating in America? Will all Madhahib agree on this position?

A 10.   The members of the Fiqh Council are well-known Muslim scholars whose knowledge and services to the Ummah are well established. We do not seek to make large claims and instead we do fear Allah and wish to follow His Messenger’s Sunnah to the best of our knowledge and capacity. We are not creating any new Madhhab and our members belong to various Madhahib, and Alhamdu’lillah they have all agreed upon this procedure for determining the Islamic dates.

Q 11.  European Islamic councils as well as other individual’s efforts have stated that by calculation 24th of September should be the first day of fasting. Why is there a difference in the results of Fiqh Council calculations?

A 11.  European Islamic councils as well as other individuals efforts may have stated that by calculation the 24th of September should be the first day of fasting. These calculations have to assume certain Matla' (May be they assumed Morocco or North America). On Sep. 22, the crescent will be 14 hours old on the West Coast of USA. This moon will not be visible in North America, although it is possible to be seen near the International Dateline southwest of Hawaii (Latitude 40:00S), where it becomes over 18 hours old.  Fiqh Council has taken the position after careful thought process and discussion that sightability (Imkan-e-Ru'yah) anywhere in the world before the end of the night in North America is acceptable to start the month. This is allowed in Fiqh.

Q. 12.  Why Fiqh Council used Greenwich Mean Time as a factor in determining Islamic days or months. What does London have to do with our faith?

A. 12.  Fiqh Council decision has nothing to do with London. It is just an alternate way to say 12:00 noon GMT instead of saying 3:00 PM Makkah time. Fiqh Council thought and discussed this 3:00 PM Makkah time, so that the moon becomes over 18 hours old at IDL in the Pacific, west of Hawaii. This moon is sightable.

Q 13.  The Imam at my Masjid says he is not going to follow the Fiqh Council’s new method and will continue to use Moon sighting reports to begin and end Ramadan.  What should I do?

A 13.  The Fiqh Council is encouraging all Muslims throughout North America to consider using the new methodology for the sake of unity and to avoid the confusion and disputes that have occurred in the past.   However, the Fiqh Council does not and does not intend to force its decision on anyone or any Muslim community.  You should follow the decision of your Imam and your Masjid.  Moreover, you should do so with great respect and avoiding unnecessary disputes and discussion.  It is not expected that everyone will embrace this decision immediately.  As with all changes, it will take time for people to understand and appreciate the new method.   But, Insha’Allah, once people see the new methodology as more objective and accurate standard, it will serve to unite us in the near future.