Methodology

How prayer times and tracking windows work

Last updated August 22, 2026

Salah Reminder is a calculation and personal-tracking tool, not a religious authority. Calculation practices and scholarly opinions differ. Follow the timetable and guidance of your trusted local mosque or qualified religious authority where it differs from the app.

Calculated locally—not fetched from a timetable API

Salah Reminder calculates prayer times on your phone using the open-source Adhan JavaScript library. The library applies astronomical calculations to the selected coordinates, date, time zone, calculation method, Asr madhhab setting, and—where supported—twilight setting. The library does not receive your coordinates or prayer history from Salah Reminder, and the app does not download daily times from a mosque or third-party prayer-time API.

Calculated results can differ from a mosque timetable because of method parameters, local adjustments, elevation, observation, high-latitude treatment, rounding, or local religious guidance.

Calculation methods offered

North America (ISNA): uses the Adhan library’s North America parameters.
Muslim World League: uses the library’s Muslim World League parameters.
Moonsighting Committee: uses the library’s seasonal Moonsighting Committee calculations and supports the twilight choices described below.
Umm al-Qura: uses the library’s Umm al-Qura parameters, including its fixed Isha interval. Salah Reminder does not currently apply a special Ramadan adjustment, so compare with an official local timetable during Ramadan.
University of Karachi: uses the library’s Karachi parameters.

Method definitions can evolve when the underlying library is updated. Salah Reminder tests library updates before releasing them, but users should still compare calculated times with an authoritative local timetable.

Asr madhhab setting

The Asr selection changes the calculated start of Asr:

Shafi, Maliki, Hanbali: maps to the Adhan library’s earlier Shafi Asr calculation.
Hanafi: maps to the library’s later Hanafi Asr calculation.

This setting changes when the app starts Asr and therefore when it closes the Dhuhr tracking window. It does not encode every ruling, exception, preferred period, necessity period, or local scholarly opinion associated with a madhhab.

Maghrib, Isha, and twilight

When Moonsighting Committee is selected, Salah Reminder exposes the Adhan library’s twilight setting:

Red twilight (Ahmer): generally produces an earlier Isha calculation and is associated by the library with Shafi, Maliki, and Hanbali usage.
White twilight (Abyad): generally produces a later Isha calculation and is associated by the library with Hanafi usage.
General twilight: the library’s combined default intended to provide reasonable results, including at higher latitudes.

For other calculation methods, Isha follows that method’s configured angle or fixed interval. The separate twilight choice does not override those methods.

How Salah Reminder marks a prayer window

For reminders and local history, the app uses the following boundaries:

Prayer being tracked	Tracking window ends at
Fajr	Calculated sunrise
Dhuhr	Calculated Asr start, based on the selected Asr madhhab
Asr	Calculated Maghrib start
Maghrib	Calculated Isha start, based on the selected method and applicable twilight choice
Isha	Calculated Fajr start the following day

If a prayer has not been marked as prayed when its tracking window ends, Salah Reminder records it locally as “Missed” and stops its reminders. A user can later correct that record.

“Missed” is an app-history status. It means the app’s configured tracking boundary passed without a completion entry. It is not a fatwa or a definitive statement about whether a prayer was valid, excused, made up, within a preferred time, or within another recognized legal period. In particular, scholarly views can differ about preferred and permissible periods for Asr and Isha and about exceptional circumstances.

What to do when a timetable differs

Confirm the location and time zone in the app.
Choose the calculation method and Asr madhhab used by your community.
For Moonsighting Committee, confirm the appropriate twilight choice.
Compare with your local mosque’s published timetable.
If a difference remains, follow your trusted local authority and report the discrepancy to support@salahreminder.app.