What is the reward for fasting six days of Shawwal?

What the reward is

The promise rests on a single well-known narration, reported by Abu Ayyub al-Ansari رضي الله عنه:

"Whoever fasts Ramadan and then follows it with six days of Shawwal, it is as though he fasted the age."— Sahih Muslim 1164a

Shaykh Ibn Baz رحمه الله explains how the arithmetic works: Ramadan counts as ten months, the six days as two, and since a good deed is rewarded tenfold, the two together come to a full year. So the person is credited with fasting the entire age — not literally, but in reward. He adds that Ramadan already expiates what lies between one Ramadan and the next, and the six days are an added good and a great benefit.

Why the scholars call it a sunnah

The six days are sunnah (a recommended practice) and never an obligation. IslamWeb states that no scholar has held them to be obligatory, either from the outset or for someone who fasted them one year — they remain recommended forever, unless a person makes a vow to fast them, in which case the vow makes them binding, not the sacred law itself. Shaykh Ibn Baz likewise describes them as "a recommended act of worship, not obligatory."

The condition that carries the full reward

The reward is not automatic. The narration's wording — "whoever fasts Ramadan, then follows it" — sets a condition, and the scholars read it strictly.

• Ramadan must be complete first: Shaykh Ibn Uthaymeen explains that a person is not described as having "fasted Ramadan" if he still owes make-up days from it. So anyone who missed days in Ramadan should make them up first, then fast the six.
• The order matters: the six come after Ramadan, in Shawwal. Fasting them before completing the make-up days does not secure this reward, even if voluntary fasting before make-up is otherwise valid.
• If Shawwal ends first: Ibn Uthaymeen notes that if the month ends before a person fasts the six, the reward is missed — unless the delay was for a valid excuse.

If you cannot complete all six

The reward is not all-or-nothing in the sense of being wasted, but the full virtue belongs to the six.

• Fasting some of them brings a reward in proportion: IslamWeb says whoever fasts part of the six is hoped to receive reward according to what he fasted, "for Allah does not waste the reward of the doers of good" — but the complete virtue is only for the one who fasts all six.
• A valid excuse is treated with generosity: Ibn Baz says that if the reason for not completing them is a legitimate excuse, the full reward is hoped for, citing the hadith that when a servant falls ill or travels, Allah records for him what he used to do while healthy and resident. No make-up is owed for what was left.
• Do not treat a partial number as the sunnah: Ibn Uthaymeen warns that one should not believe fasting five days, for instance, carries the promised reward or counts as the sunnah — the sunnah is six.

When to fast them, and combining intentions

The scholars state a preference for fasting them immediately after Eid and consecutively, because that better realises the "following" (itba') the hadith describes, and because it is a race to good before obstacles arise. But this is a recommendation, not a condition: Ibn Uthaymeen confirms they may be fasted separately or consecutively, with consecutiveness being better.

On combining intentions, Ibn Uthaymeen addresses a case where a man intended, during the six, to also count them as his three days of the monthly fast: if he completes all six with that added intention, he may attain the reward of both, since he truly fasted six days of Shawwal and three days of the month. But if he stops at three, intending only the monthly fast, he gets that reward and misses the reward of the six.

Key takeaways

• The six days of Shawwal are a recommended sunnah, never obligatory, and the reward for completing them is being credited with fasting a full year.
• The full reward requires that Ramadan be completed first; anyone owing make-up days should fast them before the six.
• Fasting part of the six brings a proportionate reward, but the complete virtue belongs to all six.
• If a valid excuse prevents completion, the full reward is hoped for, and no make-up is owed.
• Fasting them right after Eid, consecutively, is best — though fasting them separately is permitted.

Further reading

• Sahih Muslim, the chapter on the desirability of fasting six days of Shawwal
• Fatawa Arkan al-Islam, Shaykh Ibn Uthaymeen

And Allah knows best.