Question 1

Which Islamic calendar does this tool use?

Accepted Answer

This tool uses the tabular Islamic calendar (also known as arithmetic Hijri or Kuwaiti algorithm), which involves integer calculations and requires no lookup tables. It aligns with the arithmetic calendar used in most administrative and typographical contexts, providing stable and reproducible results.

Question 2

Why is the calculated date one day different from that announced by the mosque?

Accepted Answer

The months of the Islamic calendar are based on the sighting of the new moon, while the arithmetic calendar follows fixed rules. There may be a one-day difference at the beginning of the month, which is common for dates like Ramadan and Eid al-Fitr that depend on actual lunar observations. This is a normal occurrence.

Question 3

What is the supported year range?

Accepted Answer

The conversion covers a wide range of years, sufficient for historical inquiries and daily calculations. The algorithm uses Julian Day numbers as a bridge between the two calendars, all processed locally in the browser without uploading any data.

Hijri Calendar Converter

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