Date & Time
Hijri Date Difference Calculator
The span between two Islamic dates, with the Gregorian equivalent of each shown alongside.
Hijri Date Difference Calculator
Hijri dates here use the tabular (arithmetical) Islamic calendar, which is fixed and predictable. Locally observed dates depend on moon sighting and can differ by a day either way — check with your local authority for religious observances.
About the Hijri Date Difference Calculator
Enter two Islamic dates and this calculator returns the span between them — the exact number of days, plus a breakdown in Hijri years, months and days. The Gregorian equivalent of each date is shown alongside, which is usually what you need when comparing against other records.
The day count is exact. Both dates are converted to Julian Day Numbers and subtracted, so there is no drift and no accumulated error however far apart the dates sit.
Use it for anniversaries recorded on the Islamic calendar, the interval between religious observances, or the length of a period that was documented in Hijri dates.
How to use the Hijri Date Difference Calculator
- Enter the first Hijri date — year, month and day.
- Enter the second Hijri date.
- Select Calculate the difference.
- The Gregorian equivalents are shown so you can cross-check.
- Order does not matter — the earlier date is used as the start.
How the span is measured
Total days = JDN of the later date − JDN of the earlier date
Breakdown = whole Hijri years, then months, then remaining days
The Julian Day Number is a continuous day count, so the subtraction is exact.
Worked example
From 1 Ramadan 1445 to 10 Dhu al-Hijjah 1446 — the start of one Ramadan to the Eid al-Adha of the following year.
1 Ramadan 1445 falls on 11 March 2024. 10 Dhu al-Hijjah 1446 falls on 7 June 2025.
Subtracting their Julian Day Numbers gives the span directly.
453 days — 1 Hijri year, 3 months and 9 days
Both Gregorian equivalents are shown alongside your result, which is what you usually need when checking against other records.
The total days figure is the precise one. The years/months/days breakdown uses tabular month lengths, and because those alternate between 29 and 30 days, the "days" component can sit a day either side of what a strict month-by-month count would give. Where precision matters, work from the day count.
How long a Hijri year is
A tabular Hijri year runs 354 days, or 355 in a leap year. Leap years occur 11 times in every 30-year cycle, which averages the year out at 354.367 days — very close to twelve true lunar months of 29.53 days each.
| Hijri | Gregorian | Difference | |
|---|---|---|---|
| 1 year | 354.37 days | 365.24 days | 10.88 days |
| 10 years | 3,543.7 days | 3,652.4 days | 108.8 days |
| 33 years | 11,694 days | 12,053 days | 359 days |
| 100 years | 35,437 days | 36,524 days | 1,087 days |
The 33-year row is the interesting one. Thirty-three Gregorian years and thirty-four Hijri years are almost exactly the same length of time, which is why the two calendars realign on roughly that cycle.
Why the calendars drift apart
The Gregorian calendar is solar — built to track the seasons, with leap days keeping the equinoxes in place. The Hijri calendar is purely lunar and makes no seasonal correction at all.
Other lunar calendars solve this differently. The Hebrew calendar is lunisolar, inserting a thirteenth month seven times in every nineteen years to stay aligned with the seasons. The Islamic calendar deliberately does not, which is why Ramadan moves through the whole year over a lifetime — falling in long, hot summer days for some years and short winter ones in others.
The twelve Hijri months
| # | Month | Days (tabular) | Known for |
|---|---|---|---|
| 1 | Muharram | 30 | Sacred month; Ashura on the 10th |
| 2 | Safar | 29 | — |
| 3 | Rabi’ al-Awwal | 30 | Mawlid observed by many on the 12th |
| 4 | Rabi’ al-Thani | 29 | — |
| 5 | Jumada al-Ula | 30 | — |
| 6 | Jumada al-Akhirah | 29 | — |
| 7 | Rajab | 30 | Sacred month |
| 8 | Sha’ban | 29 | Precedes Ramadan |
| 9 | Ramadan | 30 | Month of fasting |
| 10 | Shawwal | 29 | Eid al-Fitr on the 1st |
| 11 | Dhu al-Qi’dah | 30 | Sacred month |
| 12 | Dhu al-Hijjah | 29 or 30 | Hajj; Eid al-Adha on the 10th |
Four are sacred months in Islamic tradition: Muharram, Rajab, Dhu al-Qi’dah and Dhu al-Hijjah. In the tabular scheme, odd-numbered months take 30 days and even-numbered ones 29, with Dhu al-Hijjah gaining a day in leap years.
Why your local calendar might differ
These dates come from the tabular calendar, which is calculated rather than observed. Real month starts depend on sighting the new crescent moon, and that varies by country, by weather and by the criteria each authority applies. A difference of ±1 day is normal and expected. For religious observance, follow your local authority.
To convert a single date rather than measure a span, use the Gregorian to Hijri converter. For age on the Islamic calendar, see the Hijri age calculator.
Common uses for counting Hijri days
Many Islamic rules are set in lunar months, not solar ones. That is why a Hijri day counter is useful.
- Iddah periods — often counted in lunar months, such as four months and ten days.
- Zakat year (hawl) — one full Hijri year, 354 or 355 days, must pass on wealth above nisab. The zakat calculator uses this rule.
- Ramadan and Hajj planning — count down to 1 Ramadan or 8 Dhul Hijjah.
- Historical dates — work out how long ago an event took place in AH years.
Need a single date converted instead? Use the Hijri to Gregorian converter.
Converting between the Hijri and Gregorian calendar
This tool counts the days between two Hijri dates. To change a single date from the Hijri calendar to the Gregorian calendar (or the other way), use the Gregorian to Hijri converter. It handles Arabic to Gregorian, Hijri to AD and Hijri to Miladi conversions.
Other ways to use this calculator
- Days between Hijri dates — enter two Hijri dates for the exact span.
- Islamic date calculator, Hijri calendar calculator and Islamic date difference — Islamic and Hijri dates mean the same calendar.
- Lunar calendar difference — spans are counted in lunar months of 29 or 30 days.
Frequently asked questions
A tabular Hijri year is 354 days, or 355 in a leap year, which averages 354.367 days across the 30-year cycle. Leap years fall 11 times in every 30. That is twelve lunar months of 29 or 30 days each, and it runs about eleven days shorter than the Gregorian year of 365.24 days.
Because the Islamic calendar is purely lunar and makes no seasonal adjustment, while the Gregorian is solar. The eleven-day annual difference accumulates, so Hijri dates move backwards through the Gregorian year and complete a full circuit in about 33 years. This is deliberate — unlike the Hebrew calendar, which adds a thirteenth month to stay aligned with the seasons.
In order: Muharram, Safar, Rabi’ al-Awwal, Rabi’ al-Thani, Jumada al-Ula, Jumada al-Akhirah, Rajab, Sha’ban, Ramadan, Shawwal, Dhu al-Qi’dah and Dhu al-Hijjah. In the tabular scheme, odd-numbered months have 30 days and even-numbered ones 29, with Dhu al-Hijjah taking an extra day in leap years. Four — Muharram, Rajab, Dhu al-Qi’dah and Dhu al-Hijjah — are sacred months.
This tool uses the tabular Islamic calendar, a fixed arithmetic scheme. Actual month starts are set by sighting the new crescent moon, which depends on weather, geography and each authority’s criteria, so countries genuinely announce different dates. A ±1 day difference from your local calendar is normal. Use the tabular figure for records and calculations, and your local authority for observance.
One Hijri year has 354 or 355 days, about 11 days shorter than a Gregorian year. Zakat is due when wealth above nisab has been held for one full Hijri year, called the hawl.
Sources and further reading
- HM Nautical Almanac Office — Islamic calendar and crescent visibility — tabular month lengths and the 30-year leap cycle
- Islamic calendar — Encyclopaedia Britannica — the twelve months and the sacred months
- US Naval Observatory — Julian date converter — the Julian Day Number system used for the exact day count