The only free converter using real Umm Al-Qura calendar data published by KACST (King Abdulaziz City for Science and Technology) — not just an astronomical formula. Accurate for Saudi government documents, ID cards, passports, and official records. Instantly shows when results differ from the standard astronomical calculation.
Most Hijri date converter websites — including large ones — use only a mathematical astronomical formula that can differ from the official Umm Al-Qura calendar by a full day. This tool uses the actual Umm Al-Qura calendar data table published by KACST for years 1318–1500 AH, and immediately flags any difference from the astronomical calculation.
The difference between an astronomical Hijri formula and the official Umm Al-Qura calendar can be a full day — and that matters for Saudi official documents, government transactions, and religious scheduling.
Uses the actual Umm Al-Qura calendar table published by King Abdulaziz City for Science and Technology (KACST) — the only official source — covering Hijri years 1318–1500 AH.
Correct for Saudi national ID cards, Iqama (residency), passports, employment contracts, court dates, and any document requiring an official Hijri date.
When the Umm Al-Qura result differs from the astronomical calculation, a badge appears immediately so you always know which date to use and why they differ.
Works directly in your browser — mobile, tablet, or desktop. No app download, no sign-up, no subscription. Convert Umm Al-Qura dates instantly and for free.
The Umm Al-Qura calendar is Saudi Arabia's official Islamic calendar, published by the King Abdulaziz City for Science and Technology (KACST). Unlike purely mathematical Hijri calendars, the Umm Al-Qura calendar determines the start of each lunar month using precisely calculated astronomical crescent moon visibility criteria specific to Mecca. It is used for all government and official transactions in Saudi Arabia, including public holidays, payroll cycles, employment contracts, legal proceedings, civil registration, and the announcement of Ramadan, Eid al-Fitr, and Eid al-Adha. The Umm Al-Qura calendar is planned years in advance, giving it predictability for administrative purposes. It is the authoritative reference for any date conversion that will appear in an official Saudi document. When precision matters — for passports, ID cards, or court filings — only the Umm Al-Qura calendar should be used.
The astronomical Hijri calculation uses a fixed mathematical formula to estimate when each lunar month begins — it is consistent, fast, and works for any year. The Umm Al-Qura calendar, published by KACST, uses a more precise method that models actual crescent moon visibility from Mecca using defined altitude and elongation thresholds at sunset. This means the two systems can disagree by exactly one day in certain months, particularly at the start of Ramadan, Shawwal (Eid al-Fitr), and Dhu al-Hijjah (Eid al-Adha). For personal or general use, the astronomical formula is perfectly adequate. For any official Saudi purpose — legal documents, government forms, passports, or religious scheduling within Saudi Arabia — the Umm Al-Qura calendar takes precedence. This tool shows both results and flags the difference when it exists.
This converter uses official Umm Al-Qura calendar data from KACST covering Hijri years 1318 AH through 1500 AH — equivalent to approximately 1900 CE through 2077 CE. This range covers virtually all practical needs: converting historical birth dates from civil records (1900s onward), checking current official Saudi dates, and looking up dates in long-term contracts or future planning up to 2077. For dates outside this range — before 1318 AH or after 1500 AH — the converter automatically falls back to the astronomical Hijri calculation and clearly labels the result so you always know which method was used. The coverage range aligns with all years for which KACST has published official Umm Al-Qura data, making this the most complete free Umm Al-Qura converter available online.
Use the Umm Al-Qura calendar for any situation requiring official Saudi accuracy: issuing or verifying national ID cards (Hawiyya), Saudi passports, Iqama (residency permits), employment contracts, tenancy agreements, court case filings, university enrollment forms, and government portal submissions. Also use it to verify the official dates of Ramadan, Eid al-Fitr, and Eid al-Adha as observed in Saudi Arabia. The astronomical calculation is sufficient for personal date tracking, planning Islamic events outside Saudi Arabia, and general-purpose Hijri-to-Gregorian conversion. If you are unsure which applies, use this tool — it shows both results simultaneously and flags any difference with a clear indicator, so you can make the right choice for your specific document or purpose without guesswork.
Understanding the difference helps you use the right date in every context.
| Criterion | Umm Al-Qura | Astronomical |
|---|---|---|
| Source | KACST (official) | Mathematical formula |
| Saudi official use | ✅ Government standard | ❌ Not official |
| Accuracy for documents | ✅ Guaranteed correct | ⚠️ May differ ±1 day |
| Year coverage | 1318–1500 AH | Any year |
| Publishable in advance | ✅ Yes (KACST) | ✅ Yes |
| Best for | Official documents | General use |
Instead of calculating dates mathematically, this converter uses a data table containing the actual first-day Gregorian date and month lengths for every Hijri month from 1318 AH to 1500 AH, extracted from the official Umm Al-Qura calendar published by KACST. When you enter a date, the tool looks up the corresponding month in this table and calculates the exact Gregorian equivalent. Simultaneously, it runs the standard astronomical Hijri formula on the same date and compares both results. If the two outputs differ — which happens in certain months, particularly at the start of Ramadan and Eid — a badge appears immediately showing both dates and labeling the difference. This transparency makes it the most reliable free Umm Al-Qura converter for official Saudi documentation purposes.
Major Islamic dates in 2025 CE with their Umm Al-Qura Hijri equivalents. Use the converter above for any specific date.
| Gregorian Date | Hijri Date (Umm Al-Qura) | Event |
|---|---|---|
| 1 Jan 2025 | 1 Rajab 1446 AH | New Year (CE) |
| 1 Mar 2025 | 1 Ramadan 1446 AH | Ramadan begins |
| 30 Mar 2025 | 1 Shawwal 1446 AH | Eid al-Fitr |
| 5 Jun 2025 | 9 Dhu al-Hijjah 1446 AH | Day of Arafah |
| 6 Jun 2025 | 10 Dhu al-Hijjah 1446 AH | Eid al-Adha |
| 1 Jul 2025 | 6 Muharram 1447 AH | — |
| 1 Jan 2026 | 2 Rajab 1447 AH | New Year (CE) |
±1 day variance possible. Verify with official KACST publications for government use.
The Umm Al-Qura calendar is Saudi Arabia's official Islamic lunar calendar, published by the King Abdulaziz City for Science and Technology (KACST). It determines the start of each Hijri month based on precisely calculated astronomical crescent moon visibility criteria for Mecca. It is used for all government, religious, and administrative purposes in Saudi Arabia and is the only calendar accepted for official Saudi documents.
Standard Hijri date converters — including most major websites — use a mathematical formula that can differ from the official Umm Al-Qura calendar by one full day in certain months. This converter uses the actual KACST Umm Al-Qura data table for 1318–1500 AH and immediately shows you when the result differs from the astronomical formula. It is the only free online tool that provides this comparison transparently.
For dates within 1318–1500 AH (1900–2077 CE), the converter uses the official KACST Umm Al-Qura data table, making it as accurate as the published KACST calendar itself. For dates outside this range, it falls back to the astronomical calculation and clearly labels the result. For critical official documents, always cross-verify with the latest KACST publication as occasional updates may occur.
The astronomical Hijri calendar uses a fixed mathematical formula based on the Tabular Islamic Calendar cycle. The Umm Al-Qura calendar, published by KACST, models actual crescent moon visibility from Mecca using specific altitude and elongation thresholds. The two systems can disagree by one day — most commonly at the start of Ramadan, Eid al-Fitr (Shawwal 1), and Eid al-Adha (Dhu al-Hijjah 10). For Saudi official use, Umm Al-Qura always takes precedence.
The converter covers Hijri years 1318 AH to 1500 AH (approximately 1900 CE to 2077 CE) using official KACST Umm Al-Qura data. Dates outside this range automatically use the astronomical Hijri calculation with a clear label. This covers all practical use cases including historical birth date conversion, current official dates, and future contract dates.
Yes. This converter is completely free with no registration, no usage limits, and no subscription required. It runs entirely in your browser — no data is sent to any server. You can convert between Hijri and Gregorian using the official Umm Al-Qura calendar as many times as needed, on any device.
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