Track the Blessed White Days

The White Days are the 13th, 14th and 15th of each Islamic (Hijri) month. Fasting them is a recommended Sunnah (mustahabb) of the Prophet Muhammad ﷺ. They are also called the "bright days" because their nights are lit by the full moon.

The Prophet ﷺ told Abu Dharr: "O Abu Dharr! When you fast three days out of a month, then fast the thirteenth, fourteenth, and fifteenth" (Jami' at-Tirmidhi 761, hasan). A similar instruction is recorded in Sunan an-Nasa'i (2424, hasan). The general hadith "fasting three days of every month is like fasting the whole year" (Sahih al-Bukhari 1976, Sahih Muslim 1159) applies to any three days; the White Days are the best choice.

The 13th, 14th and 15th of every Hijri month. Use the calendar above or the "Today" page to see the exact Gregorian dates for the current month.

Because of the whiteness of the full moon: the nights of the 13th, 14th and 15th are bright with moonlight, so these days were called "white" (al-bid).

No — it is recommended (mustahabb), not obligatory. Fasting any three days of each month is also a Sunnah; the White Days are the most virtuous choice.

Yes. Voluntary fasting is allowed on any day (except prohibited days such as the two Eids and the days of Tashreeq). Fasting all three brings the full reward mentioned in the hadiths.

During Ramadan the obligatory fast takes precedence. If the 13th of Dhul-Hijjah (a day of Tashreeq, when fasting is prohibited — Sahih Muslim 1142) falls among the White Days, fast the 14th and 15th instead, or choose other days.

The instruction to fast the 13th, 14th and 15th is attributed to the Prophet ﷺ (Tirmidhi 761; Nasa'i 2424). His own monthly fasts sometimes fell on other days — Umm Salamah reported that he fasted the first Thursday and the two Mondays of each month (Sunan an-Nasa'i 2419, sahih).