How Are Prayer Times Determined? What Is Temkin?
The times of the five daily prayers are defined in the Qur'an and the Sunnah by reference to the position of the sun in the sky. Today these times are worked out in advance by astronomical calculation and published in calendars down to the minute. In Turkey, the official prayer-times calendar is prepared by the Presidency of Religious Affairs (Diyanet).
In this article we explain, in plain terms and with sources, how each time is defined, what temkin (a small safety margin, also written "tamkin") means in the calculation, which temkin values Diyanet publishes, and why the Fajr adhan you hear at the mosque can be called at a different time from the Imsak time in the calendar.
For information only. For religious rulings, consult the Diyanet (Alo 190 Fatwa Line).
The six times defined
Daily calendars show six times: Imsak (Fajr), Sunrise, Dhuhr, Asr, Maghrib and Isha. Five of them mark the start of the obligatory prayers; one (Sunrise) marks the moment the Fajr prayer time ends.
- Imsak (Fajr): The moment the first light, known as true dawn (fajr sadiq), appears spreading horizontally along the horizon. It is the start of the Fajr prayer time and of the fast, and the end of the Isha time (TDV Encyclopedia of Islam, entries "Vakit" and "Fecir"). The vertical, rising light called false dawn (fajr kadhib), which is counted as night, falls outside this definition.
- Sunrise: The rising of the sun. The Fajr prayer time ends here and the makruh time (a time when prayer is disliked) begins.
- Dhuhr: Begins when the sun passes its highest point in the sky and starts to move west (zawal).
- Asr: Begins when the shadow of an object has grown, beyond its shadow at noon, by the length of the object itself. This measure is called the first measure (asr-i awwal). According to Abu Hanifa, the second measure (a shadow twice the object's length, asr-i thani) is the basis; however, the Diyanet calendar applies the first measure.
- Maghrib: Begins with sunset. In Ramadan it is the time of iftar.
- Isha: Begins when the glow (twilight) on the western horizon disappears and continues until Imsak.
How is the calculation done?
The times for a place are found from the latitude and longitude of that place and the height of the sun on the given date. Dhuhr is tied to the moment the sun crosses the meridian; sunrise and sunset are tied to the moment the upper edge of the sun meets the horizon. Imsak and Isha are the moments when the sun is a certain number of degrees below the horizon.
Diyanet does not state the angles it uses for Imsak and Isha clearly on its public pages. Open-source prayer-time libraries and widely used calculation services such as Aladhan model the Diyanet method with 18° for Fajr, 17° for Isha and the temkin margins below, and they give results very close to Diyanet's times. The calculations on this site by Mumin App use the same model; for this reason we use the word "calculated" on our pages and point to Diyanet for the official times.
What is temkin?
Temkin is a number of minutes added to or subtracted from the calculated value so that a single time given for a whole city or district covers the small deviations that can arise from east-west distance and differences in altitude. According to Diyanet, the purpose of temkin is to prevent a time from being treated as having begun before it actually has, and also to leave a safety margin at the end of times.
In the past, temkin was applied generously as a precaution, and the times drifted toward one another. The High Council of Religious Affairs simplified this practice in 1982; the new values came into force in 1983. Diyanet also notes that excessive temkin would bring the times closer together.
| Time | Temkin | Meaning |
|---|---|---|
| Imsak (Fajr) | 0 min | Current scholarly practice leaves no need for temkin; temkin would delay the start of the fast or move the Fajr prayer earlier. |
| Sunrise | −7 min | The latest time for the Fajr prayer ends 7 minutes before the calculated sunrise. |
| Dhuhr | +5 min | Begins 5 minutes after zawal; the temkin and makruh margin are considered together. |
| Asr | +4 min | Begins 4 minutes after the calculated first-measure (asr-i awwal) time. |
| Maghrib | +7 min | Begins 7 minutes after the calculated sunset; important so that the fast is not broken too early. |
| Isha | 0 min | No temkin is applied, for the same reason as Imsak. |
Example: Istanbul, 9 October 2026
The astronomical sunrise in Istanbul on this date is about 07:09; with the −7 minute temkin, the calendar shows sunrise at 07:02. Zawal occurs at 12:51, and with +5 minutes Dhuhr is 12:56. The astronomical sunset is 18:34; with +7 minutes Maghrib is 18:41. Imsak is 05:38 and Isha is 20:00. You can see all the times for the same day, updated daily, on our Istanbul prayer times page.
Why is the mosque's Fajr adhan called later than Imsak?
According to Diyanet's explanation, during Ramadan the Fajr adhan is called right at the beginning of Imsak; outside Ramadan it is called about one hour before sunrise. The aim is to make it easier to pray Fajr within its recommended (mustahab) time, that is, once the sky has become light. Diyanet also states that an adhan called early does not make eating forbidden, and an adhan called late does not make eating permissible; what counts is the Imsak time itself.
For this reason, outside Ramadan the Imsak time you see in the app and the Fajr adhan you hear at your neighborhood mosque can differ by about an hour. This is not an error. Because Diyanet has not published a separate precise rule for this one-hour measure, the times of the mosque adhan should be thought of as approximate values.
Why is following the calendar important?
According to Decision No. 8 of the High Council of Religious Affairs dated 18 January 2023, following the calendars is the basis for determining prayer, Imsak and iftar times. The decision states that, because temkin is applied at Maghrib, breaking the fast by mistake 2–3 minutes before the time shown in the calendar does not invalidate the fast, whereas if iftar is made earlier than that, the fast must be made up (qada). This detail shows why the exact minute of the times matters.
Times at high latitudes
In places north of 45° latitude, true dawn and twilight may not disappear completely in the summer months. In its 2009 decision, the High Council of Religious Affairs accepted that for these regions Isha should be estimated to begin one third of the legal night after Maghrib, and at most 1 hour 20 minutes after Maghrib. Beyond 62° latitude, the times of 62° are used. Since the whole of Turkey lies south of this limit, this rule is not applied in our provincial centers.
Frequently asked questions
How many minutes is temkin?
The values published by Diyanet are: Imsak 0, sunrise −7, Dhuhr +5, Asr +4, Maghrib +7, Isha 0 minutes. This system was simplified by a High Council of Religious Affairs decision in 1982 and came into force in 1983.
How is the Asr time calculated in the Diyanet calendar?
The Diyanet calendar uses the first measure (asr-i awwal): Asr begins when the shadow equals the object's length in addition to its noon shadow. Abu Hanifa's view, the second measure (asr-i thani, two times the length), is not shown in the calendar.
Can the times in the app differ from the Diyanet calendar?
Between the official district-based times and a calculation made from a provincial center's coordinates, a difference of a minute or two may arise because of coordinates, altitude and rounding. For the official times, consult Diyanet's namazvakitleri.diyanet.gov.tr page.
Sources
- Diyanet İşleri Başkanlığı, Vakit Hesaplama: Temkin
- Diyanet İşleri Başkanlığı, Vakit Hesaplama: İmsak
- Diyanet İşleri Başkanlığı, Vakit Hesaplama: Sabah Ezanı
- Diyanet Din İşleri Yüksek Kurulu, İkindi namazının vakti ne zaman başlar ve ne zaman sona erer?
- Diyanet Din İşleri Yüksek Kurulu, Karar 8 (18.01.2023): Akşam ezanının yanlışlıkla bir iki dakika erken…
- Diyanet Din İşleri Yüksek Kurulu, 45. Enlemin Ötesinde Namaz Vakitleri (10.06.2009)
- TDV İslâm Ansiklopedisi, Vakit maddesi
- TDV İslâm Ansiklopedisi, Fecir maddesi
- Aladhan API, calculation methods (Turkey, method 13) and adhan-js CalculationMethod: open-source modeling of the Diyanet approach
For information only. For religious rulings, consult the Diyanet (Alo 190 Fatwa Line).
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