2026-09-08
Prayer Times in the United States: The ISNA Method Explained
If you have ever compared two prayer apps in the United States, you have probably noticed they disagree. Sometimes by two minutes, sometimes by twenty. Neither app is broken. Prayer times are not observed but calculated from the position of the sun, and at several points in that calculation different institutions plug in different numbers. Here is where the American differences come from.
ISNA is the de facto American standard
The Islamic Society of North America publishes a calculation that uses 15 degrees of solar depression for both Fajr and Isha. Most mosques across the United States and Canada follow it, and most American prayer apps default to it. It is not an official standard in any legal sense — there is no body in North America with the authority to set one — but it is by a wide margin the most common.
Why 15 degrees and not 18
The Muslim World League, used across much of the world, sets Fajr at 18 degrees and Isha at 17. ISNA's 15 degrees produces a later Fajr and an earlier Isha. The reasoning usually given is practical: at North American latitudes, an 18-degree Fajr falls very early in summer, and in the northern states the angle is not reached at all for several weeks. A shallower angle keeps the times workable through the year. Whether one prefers the earlier or later value is a question of which scholarly position one follows, not of arithmetic.
How big is the difference?
Three degrees of depression translates to roughly twelve to twenty-five minutes in the continental United States, depending on season and latitude. In practice that means a Fajr difference large enough to matter for suhoor during Ramadan, and an Isha difference large enough to change whether you pray before or after a typical evening schedule. Dhuhr, Asr, Maghrib and sunrise are barely affected, because they do not depend on the twilight angle at all.
The Asr question
Asr begins when an object's shadow reaches a set multiple of its own length. In the Shafi'i, Maliki and Hanbali understanding the multiple is one; in the Hanafi understanding it is two. That single choice moves Asr by twenty minutes to an hour depending on the season. ISNA publishes the one-shadow value, and that is what most American timetables show. Many mosques founded by South Asian communities post the two-shadow value alongside it. Both are internally consistent; which one you follow depends on your madhhab.
What QiblaTap shows for US cities
We use the ISNA calculation for the United States and Canada, with the one-shadow Asr, because that matches what the large majority of North American mosques publish. We checked our output against the ISNA reference for New York, Chicago, Los Angeles and Toronto on 8 September 2026 and the largest gap on any prayer was two minutes. The method in use is printed under every prayer times table.
What to do when sources disagree
If you pray regularly at a particular masjid, its timetable is the practical reference — if only so you do not miss the congregation. If you are praying alone, following your community's method is the natural choice. Where two sources differ by a few minutes, taking the cautious side is a calm habit: the earlier time for Fajr, the later one for breaking a fast. None of these methods is wrong; they are the same astronomy with different assumptions.