Start by comparing the same kind of time
If a mosque timetable shows two columns, check which one you are reading. The prayer-start or beginning column describes when the prayer period opens; the iqamah column is the scheduled congregation. SalahTable calculates prayer starts and does not publish a mosque's congregation schedule.
For example, a mosque could schedule its congregation 20 minutes after the start. That gap would not mean that the app's calculation is 20 minutes wrong. For attending a congregation, check the mosque's own published timetable.
What settings can change the answer?
- Calculation method: Fajr and Isha depend on the selected convention. Some methods use twilight angles; others use a fixed interval for Isha or seasonal adjustments.
- Asr convention: selecting Hanafi changes Asr. It does not by itself change Fajr or Maghrib.
- Location: a city-centre calculation and a calculation for your exact coordinates need not match. Check that two places with the same name are in the same country.
- Date and time zone: use the city's local calendar date. A wrong daylight-saving setting can introduce an hour-scale discrepancy.
- Local adjustments: a timetable may include precautionary minutes, rounding or a locally adopted seasonal schedule.
A worked example: Karachi, 21 March 2027
Both rows use the same coordinates (24.8608°, 67.0104°), date and time zone (Asia/Karachi). Only the method changes; Asr is shown separately for each convention.
| Method | Fajr | Shafi‘i Asr | Hanafi Asr | Isha |
|---|---|---|---|---|
| ISNA (15° / 15°) | 5:33 AM | 4:06 PM | 5:02 PM | 7:46 PM |
| Karachi (18° / 18°) | 5:20 AM | 4:06 PM | 5:02 PM | 7:59 PM |
In this example, Karachi-method Fajr is 13 minutes earlier than ISNA Fajr. That is a comparison of two calculations, not a measurement establishing which timetable matches observed dawn.
See Karachi for today's times and the method selector. The example above stays on a fixed date so it can be reproduced.
How to investigate a mismatch
- Match the city, local date and time zone.
- Compare prayer starts with prayer starts, rather than congregation times.
- Match the calculation method and Asr selection.
- Check whether the timetable lists added minutes or a summer rule.
- If a difference remains, ask the timetable publisher which convention it uses.
A one-minute difference alone does not identify an error; rounding and local inputs matter. A larger difference also needs context before choosing a setting. We explain SalahTable's defaults and published-timetable checks on the methodology page.
Why can summer differences be larger?
At high latitudes the sun may not reach a chosen twilight angle. A calculation then needs an alternative rule, so matching only an angle is insufficient. See the high-latitude data page for affected cities and dates.