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Voluntary Fasting in the Sunnah
Beyond the fard of Ramadan, the Prophet ﷺ kept and encouraged particular voluntary fasts — each with a clear reward, and each meant as a way to draw near, not a burden to overload the soul.
Ramadan is the one obligatory fast of the year. Everything on this page is nafl — voluntary, recommended, rewarded, but never required. The Prophet ﷺ set aside certain days and encouraged them, and he also warned against fasting on two days entirely and against singling out one day. The point throughout is nearness to Allah with ease: take up what you can keep, and do not turn a gift into a chain.
For the obligatory month see Ramadan; for how these fasts sit within daily worship see Practice; and to place the lunar dates below see the Islamic calendar.
Voluntary fasting is a private act between a servant and Allah. In the hadith qudsi the Prophet ﷺ reported that Allah said, "Every deed of the son of Adam is for him except fasting; it is for Me, and I shall reward it." The reward is real, but the Prophet ﷺ also cautioned against overreaching: he told a companion who wanted to fast every day that "the one who fasts perpetually has not fasted," and he steered him toward a sustainable measure instead. Choose fasts you can keep, and let them lighten the heart rather than exhaust the body.
The recommended fasts of the Sunnah, each with its timing and reward — and, in red, the days on which fasting is forbidden.
A calendar of voluntary fasting in two parts. Part one, the recommended fasts of the Sunnah, each with when it falls and its reward. Mondays and Thursdays: every week, the days deeds are raised to Allah. The white days (ayyam al-bid): the 13th, 14th and 15th of every lunar month, carrying the reward of fasting the whole month. Six of Shawwal: any six days of the month after Ramadan, which with Ramadan equal the reward of fasting the entire year. Ashura: the 9th and 10th of Muharram, which expiates the year that came before it. Arafah: the 9th of Dhul-Hijjah, expiating the year before and the year after — but only for those not performing Hajj; pilgrims do not fast it. The fast of Dawud: fast one day, break the next, alternating — the most beloved fast to Allah and the ceiling of voluntary fasting. Part two, in red, the days you must never fast: the two Eids — Eid al-Fitr and Eid al-Adha; the three days of Tashriq, the 11th, 12th and 13th of Dhul-Hijjah; and Friday singled out alone, unless joined to the day before or after it.
🗓️ Mondays & Thursdays
Every week
The days deeds are raised to Allah — the easiest steady weekly habit.
🌕 The white days
13 · 14 · 15 of each lunar month
Three days a month carries the reward of fasting the whole month.
🌙 Six of Shawwal
Any six days after Ramadan
With Ramadan, as though one fasted the entire year.
🕊️ Ashura
9 & 10 Muharram
Expiates the year before it. The day Allah saved Musa.
🏜️ Arafah
9 Dhul-Hijjah · not for pilgrims
Expiates the year before and after. Pilgrims at Arafah do not fast.
⚖️ Fast of Dawud
Alternate days, all year
Fast a day, break a day — the most beloved fast to Allah, and its ceiling.
🚫 Days you must never fast
Forbidden, not rewarded — however sincere the intention.
The two Eids — Eid al-Fitr & Eid al-Adha
The days of Tashriq — 11, 12, 13 Dhul-Hijjah
Friday alone — unless joined to a day before or after
Mondays and Thursdays
🗓️ The two weekly days
The Prophet ﷺ used to fast Mondays and Thursdays. He gave two reasons. First, deeds are raised to Allah on these days: "Deeds are presented on Monday and Thursday, and I love that my deeds be presented while I am fasting" (Jami' at-Tirmidhi 747). Second, when asked about fasting on Monday specifically, he answered: "It is (the day) when I was born and revelation was sent down to me" (Sahih Muslim — site reader no. 2634 (Kitāb aṣ-Ṣiyām)) — the day of his birth and of the first revelation.
These two days recur every week, which makes them the easiest voluntary fast to build a steady habit around.
Fasting three days of each month is a standing sunnah, and the Prophet ﷺ made three of his three-part advice to Abu Hurayrah: "My friend (the Prophet (ﷺ) ) advised me to observe three things: (1) to fast three days a month; (2) to pray two rak`at of Duha prayer (forenoon prayer); and (3) to pray witr before sleeping" (Sahih al-Bukhari 1981). The three days are best kept on the ayyam al-bid — the "white days," the 13th, 14th and 15th of the lunar month, when the moon is full and bright.
Because three days a month works out to roughly one in ten, it carries the reward of fasting the whole month, since a good deed is multiplied tenfold.
Refs: three days every month — Sahih al-Bukhari 1981; the white days as 13, 14, 15 — Jami' at-Tirmidhi 761 (graded ṣaḥīḥ in the site's hadith repository) and al-Nasa'i.
Six days of Shawwal
🌙 Six after Ramadan
After completing Ramadan, six voluntary days in the following month of Shawwal carry an extraordinary reward. The Prophet ﷺ said: "He who observed the fast of Ramadan and then followed it with six (fasts) of Shawwal. it would be as if he fasted perpetually" (Sahih Muslim — site reader no. 2642 (Kitāb aṣ-Ṣiyām)) — that is, the entire year. The six may be kept together or spread across the month; they need not directly follow Eid. Scholars note the arithmetic behind the promise: the month of Ramadan counts as ten months in reward, and the six days as two more, completing a full year.
Whoever still owes make-up days from Ramadan should give those priority; many scholars hold the "whole year" reward belongs to the one who first completes the obligatory month.
Ashura, the 10th of Muharram, marks the day Allah delivered Musa and his people and drowned Pharaoh. The Prophet ﷺ fasted it and, asked about it, said: "It expiates the sins of the preceding year" (Sahih Muslim — site reader no. 2631 (Kitāb aṣ-Ṣiyām)). Toward the end of his life he intended to distinguish the Muslim fast from that of the People of the Book by adding the ninth: "If I live till the next (year), I would definitely observe fast on the 9th" (Sahih Muslim — site reader no. 2551 (Kitāb aṣ-Ṣiyām)) — so the sunnah is to fast the 9th and 10th together.
The 9th of Dhul-Hijjah, the Day of Arafah, is the greatest day of the year. For those who are not performing Hajj, fasting it is strongly recommended: the Prophet ﷺ said: "It expiates the sins of the preceding year and the coming year" (Sahih Muslim — site reader no. 2631 (Kitāb aṣ-Ṣiyām)). Pilgrims standing at Arafah do not fast that day — the Prophet ﷺ stood there not fasting, and a fasting pilgrim would be weakened for the day's du'a and worship.
When a companion pressed to fast more and more, the Prophet ﷺ guided him to the fast of the Prophet Dawud (David), peace be upon him: "Fast one day and give up fasting for a day and that is the fasting of Prophet David and that is the best fasting" (Sahih al-Bukhari 1976). It is the ceiling of voluntary fasting — the Prophet ﷺ said no fasting is better than fasting half the year in this way, and warned that the one who fasts every single day has not truly fasted. Alternating days keeps rights fulfilled toward one's body, family, and worship.
Aisha, may Allah be pleased with her, reported that the Prophet ﷺ fasted more in Shaban than in any other month outside Ramadan: "I never saw Allah's Messenger (ﷺ) fasting for a whole month except the month of Ramadan, and did not see him fasting in any month more than in the month of Sha'ban" (Sahih al-Bukhari 1969). Increasing voluntary fasts in Shaban prepares the body and heart for the obligatory month that follows. This is about fasting generally through the month — not singling out its middle night for a special ritual fast or prayer, for which no authentic prophetic practice is established.
Fasting is forbidden on the two festival days — Eid al-Fitr and Eid al-Adha. Abu Sa'id al-Khudri reported that the Prophet ﷺ "forbade the fasting of `Id-ul-Fitr and `Id-ul-Adha (two feast days)" (Sahih al-Bukhari 1991). These are days Allah has appointed for eating, gratitude, and celebration; to fast them contradicts the very purpose of the day. (The three days of Tashriq following Eid al-Adha — the 11th, 12th and 13th of Dhul-Hijjah — are likewise not to be fasted except in a specific allowance for a pilgrim who could not find a sacrifice.)
The Prophet ﷺ prohibited singling out Friday for fasting: "None of you should fast on Friday unless he fasts a day before or after it" (Sahih al-Bukhari 1985). Friday is the weekly Eid of the believers, a day for Jumu'ah and du'a. There is no harm in fasting it if it falls within a habit — such as the fast of Dawud or a white day landing on Friday, or fasting Thursday-and-Friday or Friday-and-Saturday together. The prohibition is only against picking out Friday on its own.
Voluntary fasting is wide and generous, but it has limits the Prophet ﷺ set. Guard against three things that people sometimes add:
Fasting the two Eids or the days of Tashriq as if it were extra piety — it is forbidden, not rewarded.
Singling out Friday, or Saturday, alone — pair it with an adjacent day or keep it only within an existing pattern.
Inventing fixed "special" fasts with no authentic evidence — such as a set annual fast on a particular night — however sincere the motive. The recommended fasts above are the ones the Prophet ﷺ actually kept and named.
Voluntary fasting is a door Allah has opened wide — take up what you can hold to, keep it steady, and let it draw you nearer without wearing you down.
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