Ramadan Date Estimator

Enter a Gregorian year to estimate when Ramadan — the 9th month of the Islamic (Hijri) calendar and the month of fasting — begins. The tool finds the Hijri year whose Ramadan falls inside your chosen Gregorian year and shows the estimated start date with its weekday. It is useful for travel, work and school planning, but the true date is set by moon sighting.

Why the date drifts through the seasons

The Islamic (Hijri) calendar is purely lunar — each month begins at the new crescent moon. A Hijri year is approximately 354 days, about 11 days shorter than the 365-day Gregorian year. This means Ramadan moves roughly 11 days earlier each Gregorian year, completing a full cycle through all seasons over roughly 33 years. For a few years, a high Gregorian year can contain two partial Hijri months of the same name, or a Ramadan start that falls very late in December, causing the following Ramadan to start within the same Gregorian year — though this is rare.

How it works

The tool uses the tabular Islamic calendar (the arithmetical “Kuwaiti” civil algorithm), which assigns a fixed pattern of 29- and 30-day months and 11 leap years per 30-year cycle. It converts 1 Ramadan of the relevant Hijri year to a Julian Day Number (JDN), then converts that JDN to a Gregorian date using the standard Fliegel–Van Flandern inverse, which also yields the weekday.

To pick the right Hijri year, it approximates AH ≈ (Gregorian − 622) × 33 ÷ 32, then checks the year before, that year, and the year after so the returned 1 Ramadan always lands inside the Gregorian year you entered. Because this is arithmetic, the result is deterministic — but the announced start, fixed by physical moon sighting, can differ by 1–2 days and varies by country.

Why countries announce different start dates

The crescent moon must be sighted — by eye, telescope, or astronomical calculation, depending on local religious authority — to confirm the new month. Whether the moon is visible depends on the observer’s latitude, weather, and sight conditions. Countries that use local sighting can start Ramadan a day earlier or later than countries that follow the Saudi Arabian announcement. Some communities in Western countries follow the nearest Muslim-majority country’s declaration. This is a long-standing and accepted variation in Islamic jurisprudence; the difference is typically just one day.

Example and recent years

Entering 2026 finds Hijri year 1447 AH and estimates 1 Ramadan at around 18 February 2026. The following year, 2027, it shifts roughly 11 days earlier to early February — illustrating how the lunar month drifts backward through the Gregorian seasons each year.

Always confirm with a local religious authority or official announcement before making firm travel or work arrangements. This tool is privacy-first — everything runs in your browser and nothing is sent anywhere.