Fasting on the white days
This article was first published in November 2021 and has been updated as of July 2026.
Have you tried voluntary fasting on Monday or Thursday? Do you know that you can also fast on the white days? Do you know which days are white days? Today, the practice of fasting on the white days is often forgotten by many. This article intends to reintroduce this beautiful prophetic practice in hopes that it will not be considered a forgotten sunnah.
What are the white days?
The white days, or known as 'Al-Ayyam al-Bid' in Arabic, are the three consecutive days that fall on every 13th, 14th and 15th day of the Islamic month. It is called white days because the full moon shines brightly throughout the three mentioned days. Hence, the radiant full moon at night symbolises the white days.
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Scientifically, the Islamic month begins with a new moon, and then it gradually expands from a crescent moon for 12 nights until it becomes a full moon which is when it radiates the brightest out of any other night, for three consecutive days. Afterwards, the moon will slowly fade away until it turns into a crescent once again and the cycle continues. One of the reasons why Prophet Muhammad s.a.w. and his companions r.a. fasted on the white days was to show gratitude towards Allah s.w.t.
Muslims are encouraged to fast during these three days on every Islamic month except for the 13th Zulhijjah as Muslims are prohibited to fast on the days of Tashriq. Prophet Muhammad s.a.w. has observed the fasting of white days and has encouraged his companions r.a. to fast along as reported by Abu Hurairah r.a. that the Prophet Muhammad s.a.w. has advised him to do three things, which are;
صِيَامِ ثَلاَثَةِ أَيَّامٍ مِنْ كُلِّ شَهْرٍ، وَرَكْعَتَي الضُّحَى، وَأَنْ أُوتِرَ قَبْلَ أَنْ أَنَامَ
“Fasting for three days every month, performing two rakaats of Dhuha prayers and praying witr before sleep.”
What are the merits of fasting on the white days?
The rewards gained from fasting during the full moon are equivalent to that of fasting the whole month as reported by Abdullah Bin Amr Bin Al-As r.a. that the Messenger of Allah s.a.w. said:
صَوْمُ ثَلاَثَةِ أَيَّامٍ صَوْمُ الدَّهْرِ كُلِّهِ
“Observing fasting on three days of every month is equivalent to fasting the whole year.”
(Sahih Al-Bukhari)
The Prophet Muhammad s.a.w. himself has never failed to observe white days fasting as reported by Mu’adhah Al-‘Adawiyah r.a, that she asked the Prophet’s wife, Aisyah r.a
أَكَانَ رسولُ اللَّهِ صلَّى اللَّهُ عليهِ وسلَّمَ يصومُ ثلاثةَ أيَّامٍ مِن كلِّ شهرٍ قالت نعَم
" 'Did the Messenger of Allah s.a.w. observed three days of fasting for every month?”, She replied: 'Yes' "
(Sunan At-Tirmizi)
Thus, following in the steps of Prophet Muhammad s.a.w. fasting on white days will help us gain immense rewards. Furthermore, the greatness of the rewards of fasting is made only known to Allah s.w.t. as mentioned in a Hadith Qudsi:
كُلُّ عَمَلِ ابْنِ آدَمَ له، إلَّا الصِّيَامَ؛ فإنَّه لي، وأَنَا أجْزِي به
“Every good deed of Adam’s son is for him except fasting; it is for Me and I shall reward (the person fasting) for it.”
(Sahih Al-Bukhari)
How do we observe the fasting of white days?
To begin fasting on white days, one must make the niyyah (intention) as follows and then observe fasting as usual, from sunrise to sunset:
نَوَيتُ صَومَ أَيَّامِ البِيض سُنَّةً لله تَعَالَى
Nawaytu sauma ayyamil bidh sunnatan lillahitaa’la
I intend to observe the sunnah fast of the white days for Allah the Most High
You may also establish your intention in your heart through the language that you understand. Once you have tried fasting on white days, try to continue to fast on the following month too and eventually, In sya Allah, it will turn into a habit, just like how the Prophet Muhammad s.a.w. has the habit of observing voluntary fasting.
Let us revive and practice this forgotten sunnah together, following the Prophet Muhammad s.a.w. in pursuit of Allah's s.w.t. love and blessings as well as collecting rewards along the way.
To be honest, I myself am trying to observe fasting on white days, though some months I did not manage to do so. Nevertheless, it feels great to practice the sunnah and I enjoyed sharing about it with the people around me. I highly encourage my fellow readers to try it out. So, come join me, let’s challenge ourselves to observe these three days of fasting and may Allah s.w.t. grant us the strength to ace this challenge. Amin.
And Allah knows best.
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