The Islamic calendar system operates on lunar observations, meaning that the declaration of a new month depends on human sightings of the moon. This aspect introduces variability and makes it unsuitable for precise computer calculations.
iman Pro utilizes an arithmetic Islamic calendar, which is an approximation of the true calendar. Consequently, it may not be as accurate as calendars declared by local authorities, as these can vary from one region to another.
However, the app offers a manual correction tool for the calendar. This feature can be found in the app settings, allowing users to adjust the current date by adding or subtracting one day.