Which prayer calculation method should I use?

Use whichever method your local mosque uses — this ensures you can pray with the congregation and follow your imam's Iftar/Suhoor timings during Ramadan. As regional defaults: ISNA for North America, MWL for Europe, Umm Al-Qura in Saudi Arabia, Karachi for South Asia, Egyptian for Africa/Levant. If unsure, ask your nearest masjid which method they follow.

What is the difference between Fajr angle 15° and 18°?

The number refers to how far below the horizon the sun is at Fajr. A 15° angle (ISNA) defines Fajr as starting when the sun is 15° below the horizon — closer to sunrise. An 18° angle (MWL, Karachi) defines it earlier, when the sun is 18° below — further from sunrise. The difference is typically 15–20 minutes earlier with 18°. Both are valid scholarly opinions on what constitutes 'true dawn' (Subh Sadiq).

Why does Umm Al-Qura calculate Isha differently?

Umm Al-Qura uses a fixed time offset from Maghrib (90 minutes normally, 120 minutes in Ramadan) rather than a twilight angle. This is unique to Saudi Arabia and was adopted for practical and historical reasons — at Mecca's latitude (21.4°N) the twilight angle method works fine, but the fixed offset is what the Saudi religious authority codified. During Ramadan the longer 120-min gap gives families enough time to break fast, pray Maghrib, eat, and reach the mosque before Isha and Tarawih.

What is the Hanafi vs Shafi'i Asr difference?

Asr time is determined by an object's shadow length. The majority (Shafi'i, Hanbali, Maliki) say Asr begins when shadow = object height + the morning's residual shadow. The Hanafi school says Asr begins later, when shadow = 2× object height + residual. In practice, Hanafi Asr is roughly 45–90 minutes later than Shafi'i Asr depending on season and latitude. This is configured separately from the Fajr/Isha calculation method.

Can I switch methods if I move countries?

Yes. The recommendation is to follow the method used by your new local mosque so you pray in sync with the community. If you live in a place with multiple mosques following different methods, picking any of them is valid — they are all based on classical scholarship. Picking based on the nearest congregational mosque is most practical.

Do calculation methods affect Dhuhr, Asr, and Maghrib?

Mostly no. Dhuhr is set by the sun's zenith (solar noon) — every method agrees on this within a minute. Maghrib is sunset (apparent disk fully below horizon) — also agreed except Shia who add a few minutes. Asr depends on madhab (Hanafi vs majority) not calculation method. The methods diverge mainly on FAJR (twilight before sunrise) and ISHA (twilight after sunset) because there is no observable horizon event for these — they are defined by sun depression angle, and scholars chose different angles.

Prayer Calculation Methods Explained: ISNA, MWL, Umm Al-Qura, Karachi (Which to Use)

Have you ever noticed your prayer app shows Fajr at 4:42 AM while your local mosque says 4:58 AM? You're not seeing a bug — you're seeing two different calculation methods. Three of the five daily prayers (Dhuhr, Asr, Maghrib) are anchored to clearly observable solar events: noon, a specific shadow length, and sunset. But Fajr and Isha are defined by twilight — the time before sunrise and after sunset when the sun is below the horizon but the sky is still lit.Different schools of Islamic jurisprudence chose different sun depression angles to define when twilight begins and ends, and that's why prayer time apps and mosques can disagree.

The seven main calculation methods

Below are the seven methods supported by every major prayer time app and used by virtually every Muslim country. The numbers are the sun's depression below the horizon (in degrees) used to define Fajr and Isha.

Method	Fajr angle	Isha angle	Used in
ISNA — Islamic Society of North America	15°	15°	United States, Canada
MWL — Muslim World League	18°	17°	Europe, Far East, parts of Africa
Umm Al-Qura — Saudi Arabia	18.5°	90 min after Maghrib (Ramadan: 120 min)	Saudi Arabia, GCC
Egyptian — Egyptian General Authority of Survey	19.5°	17.5°	Egypt, Africa, Levant
Karachi — University of Islamic Sciences	18°	18°	Pakistan, India, Bangladesh, Afghanistan
Tehran — Institute of Geophysics, University of Tehran	17.7°	14°	Iran, Shia communities
Jafari — Shia Ithna Ashari	16°	14°	Iraq, Lebanon (Shia)

What the "angle" actually means

Imagine the sun sinking below the horizon. At the moment it disappears, that's sunset (Maghrib). But the sky stays bright for a while after — first the bright red and orange of civil twilight, then the deeper blue of nautical twilight, then finally true darkness (astronomical twilight ends).

The sun's position below the horizon is measured in degrees:

0° — sun on the horizon (sunset / sunrise itself)
6° below — civil twilight ends (lights typically come on)
12° below — nautical twilight ends (horizon barely visible)
15°–19° below — astronomical twilight (sky fully dark)

Fajr is the reverse: as the sun rises toward the horizon before sunrise, the sky starts to lighten. Subh Sadiq("true dawn") is the first white light spreading horizontally — the moment Fajr begins, distinguished from Subh Kadhib("false dawn,") a vertical pillar of light that appears briefly and fades.

Different scholars studied true dawn at different latitudes and concluded different angles. ISNA settled on 15°. MWL on 18°. The 3° difference might sound small, but it translates to roughly 15–20 minutes of clock time at moderate latitudes.

Detailed walkthrough of each method

ISNA — Islamic Society of North America

Used in: United States, Canada

Fajr: 15° · Isha: 15°

The default for most US/Canadian mosques. Adopted in 1983 after extensive consultation. Uses moderate twilight angles — narrower than MWL, so Fajr is later and Isha is earlier. Best fit for cities at moderate latitudes (25°–50°N).

MWL — Muslim World League

Used in: Europe, Far East, parts of Africa

Fajr: 18° · Isha: 17°

Headquartered in Mecca, founded in 1962. Uses wider twilight angles, so Fajr starts ~20 minutes earlier than ISNA and Isha is ~15 minutes later. Common across Europe and Asia outside South Asia.

Umm Al-Qura — Saudi Arabia

Used in: Saudi Arabia, GCC

Fajr: 18.5° · Isha: 90 min after Maghrib (Ramadan: 120 min)

Used in the two Holy Mosques (Mecca, Madinah) and all Saudi mosques. Isha is fixed at a time after Maghrib rather than a twilight angle — a unique convention. The Ramadan adjustment to 120 min gives more time to break the fast and eat before Isha.

Egyptian — Egyptian General Authority of Survey

Used in: Egypt, Africa, Levant

Fajr: 19.5° · Isha: 17.5°

Used across most of Africa, the Levant (Syria, Lebanon, Jordan, Palestine), and Egypt. Wider Fajr angle than MWL, so Fajr is earlier. Has been the standard in Egypt since 1981.

Karachi — University of Islamic Sciences

Used in: Pakistan, India, Bangladesh, Afghanistan

Fajr: 18° · Isha: 18°

Standard across South Asia, used by hundreds of millions of Muslims. Symmetric angles (18°/18°) — Fajr and Isha are equidistant from sunrise and sunset twilight respectively.

Tehran — Institute of Geophysics, University of Tehran

Used in: Iran, Shia communities

Fajr: 17.7° · Isha: 14°

Calculates Maghrib slightly after sunset (when sun is 4.5° below horizon) rather than at sunset itself — reflects Shia jurisprudence. Used widely in Iran and by Shia communities globally.

Jafari — Shia Ithna Ashari

Used in: Iraq, Lebanon (Shia)

Fajr: 16° · Isha: 14°

Similar to Tehran but with different Fajr angle. Also delays Maghrib until full sunset confirmed. Used by Shia Muslims in Iraq, Lebanon, and parts of the Gulf.

Which method should you use?

The honest answer: use whatever your local mosque uses.Praying congregationally with your community is more important than which specific calculation you follow. The reasoning is practical — if your mosque calls Fajr 15 minutes earlier than your app does, and you wait for your app, you'll miss the congregation.

If you live somewhere without an obvious local default, regional norms are:

USA / Canada → ISNA
UK, Europe, Russia → MWL
Saudi Arabia, UAE, Bahrain, Kuwait, Qatar, Oman → Umm Al-Qura
Pakistan, India, Bangladesh, Sri Lanka, Afghanistan → Karachi
Egypt, Sudan, Libya, Levant (Syria/Lebanon/Jordan/Palestine) → Egyptian
Iran, Shia communities → Tehran or Jafari
South Africa, Australia, Singapore, Malaysia → MWL or Karachi (community-dependent)

The Asr question (separate from calculation method)

Asr is configured separately because it depends on madhab (school of thought), not geographic calculation method. The split:

Standard (Shafi'i, Hanbali, Maliki)— Asr begins when an object's shadow equals its height + the residual morning shadow.
Hanafi— Asr begins later, when shadow equals 2× the object's height + residual. Roughly 45–90 minutes later than Shafi'i Asr.

We have a full breakdown in our Shafi'i vs Hanafi Asr guide.

What about high latitudes (above 48°N)?

In northern Europe (London, Berlin, Moscow), Canada, and northern US in summer, the sun doesn't go far enough below the horizon at night to ever reach 18° or even 15°. This means standard calculation methods give no Fajr or no Isha at all from May through August. Mosques use one of three correction methods:

Middle of the night — Fajr/Isha set at the midpoint between sunset and sunrise.
1/7th of the night — Isha begins 1/7 of the way through the night; Fajr 1/7 from sunrise.
Angle-based — extrapolate from the angle at lower latitudes.

For more on this, see our prayer times at northern latitudes guide.

Configuring your method

On any city page on Prayer Times Near Me, click the Settings icon to switch calculation method and madhab. We default to ISNA + Shafi'i for US visitors, MWL for European visitors, and Umm Al-Qura for Saudi visitors based on your IP — but you can override at any time.

Frequently asked questions

Which prayer calculation method should I use?: Use whichever method your local mosque uses — this ensures you can pray with the congregation and follow your imam's Iftar/Suhoor timings during Ramadan. As regional defaults: ISNA for North America, MWL for Europe, Umm Al-Qura in Saudi Arabia, Karachi for South Asia, Egyptian for Africa/Levant. If unsure, ask your nearest masjid which method they follow.
What is the difference between Fajr angle 15° and 18°?: The number refers to how far below the horizon the sun is at Fajr. A 15° angle (ISNA) defines Fajr as starting when the sun is 15° below the horizon — closer to sunrise. An 18° angle (MWL, Karachi) defines it earlier, when the sun is 18° below — further from sunrise. The difference is typically 15–20 minutes earlier with 18°. Both are valid scholarly opinions on what constitutes 'true dawn' (Subh Sadiq).
Why does Umm Al-Qura calculate Isha differently?: Umm Al-Qura uses a fixed time offset from Maghrib (90 minutes normally, 120 minutes in Ramadan) rather than a twilight angle. This is unique to Saudi Arabia and was adopted for practical and historical reasons — at Mecca's latitude (21.4°N) the twilight angle method works fine, but the fixed offset is what the Saudi religious authority codified. During Ramadan the longer 120-min gap gives families enough time to break fast, pray Maghrib, eat, and reach the mosque before Isha and Tarawih.
What is the Hanafi vs Shafi'i Asr difference?: Asr time is determined by an object's shadow length. The majority (Shafi'i, Hanbali, Maliki) say Asr begins when shadow = object height + the morning's residual shadow. The Hanafi school says Asr begins later, when shadow = 2× object height + residual. In practice, Hanafi Asr is roughly 45–90 minutes later than Shafi'i Asr depending on season and latitude. This is configured separately from the Fajr/Isha calculation method.
Can I switch methods if I move countries?: Yes. The recommendation is to follow the method used by your new local mosque so you pray in sync with the community. If you live in a place with multiple mosques following different methods, picking any of them is valid — they are all based on classical scholarship. Picking based on the nearest congregational mosque is most practical.
Do calculation methods affect Dhuhr, Asr, and Maghrib?: Mostly no. Dhuhr is set by the sun's zenith (solar noon) — every method agrees on this within a minute. Maghrib is sunset (apparent disk fully below horizon) — also agreed except Shia who add a few minutes. Asr depends on madhab (Hanafi vs majority) not calculation method. The methods diverge mainly on FAJR (twilight before sunrise) and ISHA (twilight after sunset) because there is no observable horizon event for these — they are defined by sun depression angle, and scholars chose different angles.