Find the exact Gregorian dates of the White Days (Ayyam al-Beedh) — the 13th, 14th, and 15th of every Hijri month — for fasting the recommended three days a month.
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The "White Days" (Ayyam al-Beedh) are the 13th, 14th, and 15th of every Hijri month, named for the especially bright moonlight of these nights when the moon is at or near its fullest. Voluntary fasting on these three days each month is a well-established Sunnah, drawn from multiple hadiths in Sunan Abi Dawud and Sunan al-Tirmidhi, among others, in which the Prophet Muhammad (peace be upon him) both practiced and recommended it, describing fasting three days of every month as equivalent in reward to fasting the entire month — since a good deed is multiplied tenfold, and three days multiplied by ten covers roughly a full lunar month. This calculator converts your chosen Gregorian start date into the Hijri calendar using the tabular Kuwaiti algorithm — the same conversion method used consistently across this website — to identify the Gregorian dates corresponding to the 13th, 14th, and 15th of the current or upcoming Hijri months. Because tabular calculation can occasionally differ by a day from local moon-sighting announcements, dates near the start of a Hijri month are worth double-checking against a locally trusted Islamic calendar.
Among the many recommended, non-obligatory fasts scattered throughout the Islamic calendar, few are as consistently practiced as the White Days — known in Arabic as Ayyam al-Beedh, literally "the white days." The name refers to the bright moonlit nights of the 13th, 14th, and 15th of each Hijri month, the days surrounding the full moon when the night sky is at its most illuminated.
The Sunnah of fasting these three days is documented across multiple hadith collections, including Sunan Abi Dawud and Sunan al-Tirmidhi, where companions describe the Prophet Muhammad (peace be upon him) both observing this fast personally and directly instructing others to do so. One of the most frequently cited explanations for the specific reward tied to these three days rests on a broader Qur'anic principle that a single good deed is rewarded tenfold. Three days multiplied by a tenfold reward works out to roughly thirty days — the length of an average month — which is why fasting these three days each month is often described as carrying the reward of fasting the entire month, without the difficulty of actually doing so.
Because the White Days are tied to the Hijri lunar calendar rather than the Gregorian calendar most people use for daily planning, their dates shift every month relative to the calendar on your phone or wall. Working them out by hand means first knowing exactly what Hijri date today corresponds to, then counting forward to the 13th of the current or coming Hijri month — a small but repetitive task if you want to plan several months ahead.
This calculator handles that conversion automatically, using the same tabular Kuwaiti algorithm applied consistently throughout this website's Hijri tools, so the dates you see here line up with the Hijri age calculator, the Hijri-Gregorian converter, and the rest of the Islamic tools section. Because tabular calculation is a mathematical estimate rather than an actual moon sighting, it is worth cross-checking the exact date against your local mosque or Islamic authority if you are fasting in a community that follows visual moon sighting rather than astronomical calculation. For most practical planning purposes, though, this tool gives you a reliable, ready-made schedule of White Days stretching as far ahead as you need.
The White Days are the 13th, 14th, and 15th of each Hijri month, recommended in multiple hadiths as days to fast voluntarily, with the reward described as equal to fasting an entire month.
No, it is a voluntary (Sunnah) fast, not an obligation. It is simply a highly recommended practice with a well-documented reward in the hadith literature.
Yes. While fasting all three days brings the complete described reward, fasting one or two is still a valid and rewarded voluntary fast — it does not have to be all three every month.
This tool uses tabular (calculated) Hijri dates, while many mosques follow local moon-sighting announcements, which can occasionally shift the start of a Hijri month by a day.
No — during Ramadan everyone is already fasting daily, so the White Days recommendation specifically applies to the other eleven months of the Hijri year.