Why Prayer Times Differ Between Apps and Your Local Mosque
A common question: "My app says Fajr is at 5:12 but my mosque says 5:25. Which is right?" Often both are correct. Here are the usual reasons for differences.
1. Different calculation methods
The biggest cause is the angle used for Fajr and Isha. A 15° method (ISNA) and an 18° method (Muslim World League) can differ by 15 to 30 minutes at mid-latitudes. See our comparison of methods.
2. Hanafi or Standard Asr
Asr can differ by 30 minutes to over an hour, depending on the setting. Many mosques publish the earlier time for one school and the later time for another. See Hanafi vs Shafi'i Asr.
3. Adhan time versus iqamah time
The adhan announces that the prayer time has begun. The iqamah is the call that starts the congregational prayer, and mosques usually set it 5 to 30 minutes after the adhan to allow people to arrive. A mosque timetable may list only iqamah times, which will be later than the start times in an app.
4. Safety margins
Some authorities add a few minutes of caution: for example a few minutes after calculated sunset before Maghrib, or a few minutes after solar noon before Dhuhr, so that the time has certainly begun. Some also place the end of the Fajr period a few minutes before sunrise.
5. Fixed timetables
Many mosques use a printed timetable calculated for the first day of each month or week and held for several days at a time, or round times to the nearest 5 minutes. Apps calculate each day separately.
6. Rounding and location
Apps round to the minute or truncate; some round up for Fajr and down for Isha as a precaution. Prayer times also depend on your exact location. A city timetable is calculated for a central point, so a town 50 km east may have times that are a couple of minutes earlier. For large countries or cities the difference can be noticeable.
7. Daylight saving time
Daylight saving time moves the clock by an hour, and the sun does not follow. If an app or a printed timetable is not updated on the right date, it can be an hour out. Our timetables look up the clock offset for every day, so they follow the local clock automatically.
8. Altitude and horizon
Standard calculations assume a flat sea-level horizon. At high altitude or by the sea the sun appears slightly earlier or later; hills can delay sunrise visually. These effects are mostly a minute or less but may matter for fasting accuracy.
What should you do?
- For congregational prayers, follow your mosque's timetable.
- For praying alone, use the method and school you follow, and be consistent.
- For fasting, if in doubt, stop eating a few minutes before Fajr and wait a minute or two after sunset.
On prayertim.com you can change the method and Asr school in the Options box, and our methodology page shows what each default means.