How We Calculate Prayer Times

Every prayer time on this site is calculated from the position of the sun at a specific latitude and longitude, using the convention published by a recognised Islamic authority for that country. This page explains exactly how that works, which authority we follow in each country, and why our times may differ by a few minutes from your local mosque.

The astronomical basis

The five daily prayers are defined in the Sunnah by observable states of the sky, not by clock times. Converting those states into a clock time for a given place is a problem of spherical astronomy. For any coordinate pair and calendar date, the sun’s declination and the equation of time determine when the sun reaches a given altitude relative to the local horizon. Each prayer corresponds to one of those altitudes:

• Fajr begins at true dawn (subah sadiq), when the sun is a set number of degrees below the eastern horizon and the first horizontal thread of white light appears.
• Sunrise (Shuruq) is the moment the sun’s upper limb crosses the horizon. It closes the window for Fajr.
• Dhuhr begins just after the sun crosses the local meridian, its highest point of the day (zawal). A small offset is added so the prayer is not performed at the exact instant of transit.
• Asr begins when an object’s shadow reaches a defined multiple of its own length, measured from the shadow it cast at solar noon.
• Maghrib begins at sunset, when the sun’s upper limb disappears below the horizon.
• Isha begins when the red afterglow (shafaq) has left the western sky and the sun is a set number of degrees below the horizon.

Sunrise, Dhuhr, Asr and Maghrib are geometrically unambiguous, so nearly all authorities agree on them to within a minute or two. The genuine differences between calculation methods are in Fajr and Isha, because the exact degree of twilight that counts as dawn or nightfall is a matter of scholarly judgement rather than pure geometry.

Why Fajr and Isha differ between methods

A calculation method is essentially a pair of solar depression angles. If a method specifies Fajr at 18 degrees, it means Fajr begins when the centre of the sun sits 18 degrees below the horizon. A method using 19.5 degrees will produce an earlier Fajr, because the sun reaches 19.5 degrees below the horizon before it reaches 18 degrees on its way up. The difference between the widest and narrowest conventions can be more than twenty minutes at the same location on the same day.

Two authorities also depart from the angle model for Isha. Umm al-Qura in Saudi Arabia and the Gulf and Qatar conventions define Isha as a fixed interval after Maghrib rather than a solar angle. This is why an Isha time in Makkah does not shift with the seasons the way it does in Cairo or Karachi.

Which method we use in each country

We do not apply one global default. Each country on this site is assigned the convention actually used by its national religious authority or by the body that local mosques follow, so that our times line up with the local norm rather than with an arbitrary international average.

The method in force is named on every city page, directly beneath the times table, so you always know which convention produced the numbers you are reading.

Asr and the madhab difference

Asr is the one prayer where the difference is not about twilight but about jurisprudence. Two positions are in common use:

• Shafi’i, Maliki and Hanbali: Asr begins when an object’s shadow equals its own length, plus the length of the shadow it cast at solar noon.
• Hanafi: Asr begins when the shadow reaches twice the object’s length, plus the noon shadow.

The Hanafi time is always later, typically by forty to seventy minutes depending on latitude and season. Neither is more correct than the other; they are established positions of different schools. Where a country is overwhelmingly of one school, our default reflects local practice. If you follow a different madhab from the majority in your city, take the Asr time from your own mosque.

High latitude locations

Above roughly 48 degrees of latitude there are nights in summer when the sun never falls far enough below the horizon for astronomical dawn or nightfall to occur at all. The angle model then produces no Fajr or Isha time, or produces times that collapse into each other. This affects our United Kingdom cities in June and July in particular. In these conditions the calculation falls back to a recognised approximation rather than reporting nothing, but the resulting times are estimates. If you are praying at high latitude in midsummer, follow the ruling of your local mosque or Islamic council, which will have adopted a specific position on this question.

Data, sources and refresh

Times are computed from the Aladhan astronomical service, which implements the standard algorithms and the published parameters of each authority listed above. Every city on this site carries its own stored latitude, longitude and IANA timezone identifier, so daylight saving transitions are applied automatically for countries that observe them. Results are cached and refreshed daily. When a live refresh cannot complete, the page displays the most recent cached figures and tells you it is doing so rather than showing nothing.

Why our times may differ from your mosque

A difference of a few minutes between this site and your local masjid is normal and does not mean either is wrong. The usual causes are:

• Adhan time versus iqamah time. We publish the beginning of each prayer window. Mosques usually announce a later iqamah so the congregation can gather. A twenty minute gap is common and is not a discrepancy.
• A different calculation convention. Your mosque may follow a different authority from the national default, particularly in countries with large immigrant communities.
• Precautionary minutes. Many mosques add two to five minutes to Fajr and Maghrib as a safety margin.
• Position within the city. Our figures use a single representative coordinate for each city. Across a large metropolitan area the true times can vary by one to three minutes.
• Local elevation and horizon. Mountains or tall buildings change the visible horizon, which affects observed sunrise and sunset.

Where the two disagree, your local mosque is the authority for your congregation. We are a reference for planning, not a replacement for it.

Corrections

If you believe a time, coordinate or calculation method on this site is wrong for your city, please tell us. Include the city, the date and the figure you expected, and cite the authority you are comparing against. We check every report and correct genuine errors. Our process for handling reports is set out in our editorial and corrections policy.