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Convert Hijri (Islamic) to Gregorian
If you have an Islamic (Hijri) date and need its Gregorian equivalent, use the converter above or visit our dedicated Hijri to Gregorian converter tool page.
Common use cases include:
- Registering a birth date on an international platform
- Filling out a form that uses Gregorian dates
- Matching a document written in the Hijri calendar
Convert Gregorian to Islamic (Hijri)
If you have a Gregorian date (like an appointment, certificate, or record) and need its Islamic equivalent, you can convert it directly here or visit our Gregorian to Islamic converter tool.
Everyday Applications:
- Finding the Hijri date of a specific occasion
- Matching dates within local systems
- Calculating age between two dates in different calendars
The Science Behind Date Conversion
Date conversion is complex because the Hijri and Gregorian lunar and solar cycles differ. A Hijri year is typically 10 to 11 days shorter than a Gregorian year, causing Hijri dates to shift continuously relative to the Gregorian calendar.
For accurate results, a tool must rely on official calendar data specific to the country that adopts it.
This is why most reliable sources depend on the Umm al-Qura calendar. To understand its superior accuracy, it helps to know how it is constructed.
How Is the Umm al-Qura Calendar Actually Built?
The Umm al-Qura calendar is based on a fixed calculation model that determines the start of each lunar month. These rules are then compiled into comprehensive data tables covering many years, making it the standard for official systems.
Consequently, tools that utilize these specific data tables yield much higher accuracy than other methods.
In addition, you can read more information about the calendar used in our tool on the Umm al-Qura calendar page on Wikipedia.
Umm al-Qura vs. Astronomical Calculations vs. Moon Sighting
There are several ways to determine the beginning of Hijri months, and the most common methods are:
- Umm al-Qura calendar relies on fixed calculation rules that produce an official, structured calendar, and it is used in systems and transactions within Saudi Arabia.
- General astronomical calculation relies on astronomical criteria that may differ from one source to another, so slight differences may appear between tools.
- Local moon sighting depends on an official announcement after the sighting is verified by the relevant authority in each country.
Why Do Results Vary Across Different Tools?
Discrepancies usually stem from differences in calculation methods or the base calendar reference. Some tools use general astronomical models, while others rely on official calendars.
For example, if the Hijri date 1 Ramadan 1445 is converted, some tools may give the result March 10, 2024, while the Umm al-Qura calendar gives March 11, 2024.
Common Conversion Inaccuracies
Conversion inaccuracies typically occur when tools rely on:
- An approximate Hijri calendar
- General formulas instead of actual calendar data
- Incorrect handling of the start of the day or time
For example, some websites use approximate formulas such as:
Gregorian Date ≈ Hijri Date × 0.97 + 622
This formula gives only a general estimate, but it does not rely on actual calendar data for each year. Sometimes it gives a close result, but in some years it can be off by a day or more.
Accuracy of the Results
Accuracy depends on the range of years covered by the tool's underlying calendar library. For instance, our date converter uses the Umm al-Qura calendar library tabby-ai/hijri-converter which supports conversion from 1343 AH to 1500 AH with high accuracy.
As long as the date to be converted falls within the covered year range of the Umm al-Qura calendar, the conversion results will be accurate and consistent with the calendar used in systems within Saudi Arabia.
Dates that fall outside the covered year range are calculated according to known astronomical models.
When to Check Official Announcements
If the date is related to an official transaction, a legal matter, a religious procedure, or an official announcement for a religious occasion, then the correct reference is the official announcement issued by the relevant authority in your country.
Frequently Asked Questions
Is date conversion based on the Umm al-Qura calendar officially recognized?
Yes, in most systems that rely on the Umm al-Qura reference.
Why do I see a one-day difference when converting dates?
Because of the difference in the reference used by the date converter to determine the beginning of the lunar month.
Can future dates be converted?
Yes, they can be converted within the supported calculation range, but their accuracy cannot be fully guaranteed.
Is the conversion accurate for all years?
Yes, accuracy is higher within the year range covered by the calendar data.
The goal of the tool is simple:
simply enter the date you have, then view the corresponding date in the other calendar.