Prayer time calculation methods and settings

What the calculator needs

The calculator works through five steps in a fixed order:

1. Place and date. Latitude, longitude and a Gregorian date fix the sun’s path through that day. This gives solar noon, sunrise, sunset and how far below the horizon the sun goes at night.
2. Criteria. The method profile sets how Fajr and Isha are found. Most profiles use an angle of the sun below the horizon. Some set Isha as a fixed interval instead. The Moonsighting Committee profile uses an 18° base angle kept within seasonal limits, and its twilight type setting also affects Isha. Custom adds dated Isha options. The Asr setting picks a shadow length. The night rule limits Fajr, and an angle-based Isha, when the night is short.
3. Angle times for Fajr and Isha. For an angle-based Fajr or Isha, the tool works out the height of the sun’s centre at a series of candidate moments. It then narrows in on the moment the sun crosses the selected angle. Fajr is the crossing while the sun is rising before solar noon. Isha is the crossing while the sun is setting after solar noon. The tool also checks the lowest point the sun actually reaches that night. If the sun never gets as far below the horizon as the angle, there is no crossing, and the next step sets the time instead. The Moonsighting Committee profile uses this step to find its 18° starting times. Two kinds of Isha skip this step: a fixed-interval Isha and an active date-window interval in Custom. Both are counted from their start point.
4. Limits, adjustments and rounding. The selected night rule is applied next. It limits Fajr, and an angle-based Isha, when the crossing is missing or falls beyond the limit. The Moonsighting Committee profile applies its own seasonal limits here instead. In Custom, an active date-window cap can then move Isha earlier. Built-in profile adjustments and any manual minutes are added next, and your own Isha minutes are always added last. Each time is then rounded to the nearest minute.
5. Timezone. The results so far are calculated instants that are not yet tied to a local clock. The place’s timezone converts them into local clock times, including daylight saving.

The method and the timezone are independent. Changing the method can move the moment Fajr begins. Changing the timezone only changes the clock label on that same moment.

All of these steps run in your browser with built-in data. Your location is not sent to a prayer-time service.

The calculator is built on version 4.4.6 of the Adhan JavaScript library, whose Adhan 4.4.6 method documentation and Adhan 4.4.6 usage guide describe these inputs. Adhan supplies the method profiles, sunrise, sunset, solar noon, Asr, the fixed Isha interval and the Moonsighting Committee seasonal model. It also supplies three of the night-rule shares: twilight angle, middle of the night and one seventh. The angle step for Fajr and Isha described above is our own addition, called Qibla Finder Online twilight refinement 1. The original, unmodified Adhan library does not include this step. If you run that library with the same settings, it will not always reproduce our angle-based Fajr and Isha times. The same is true of Moonsighting Committee times, because this tool finds the 18° times with the same angle step before it applies the seasonal limits.

Compare the supported profiles

The tool offers nine profiles. Each profile is a set of numbers. The profile table on this page lists them in the same units for every profile: Fajr angle, Isha angle or interval, and any built-in adjustments. Several points in the table are easy to misread:

• FCNA Canada (13° / 13°) is not the same as ISNA. It starts from the library’s North America preset, sets both Fajr and Isha to 13°, and keeps that preset’s built-in +1 minute on Dhuhr. The ISNA / North America profile keeps 15° for both. A smaller angle is reached closer to sunrise and sunset. So before any night limit is applied, 13° gives a later Fajr and an earlier Isha than 15°. On a short summer night, a night limit can place both profiles at the same time. The 13° values follow the Fiqh Council of North America’s suggested method for Fajr and Isha. That is the Council’s recommendation, not a description of what every Canadian mosque uses.
• Other angle profiles. Muslim World League (18° / 17°), Karachi (18° / 18°) and Egyptian (19.5° / 17.5°) use angles for both prayers. Like the two North American profiles, each adds +1 minute to Dhuhr.
• Umm al-Qura sets Isha by interval. Fajr uses 18.5°, and Isha comes a fixed 90 or 120 minutes after sunset, with no built-in Dhuhr adjustment. The 120-minute option is often used during Ramadan. The tool does not track the lunar calendar, so select it yourself when your community uses it.
• Moonsighting Committee (seasonal twilight) starts from 18°, but 18° is not a guaranteed crossing. The table describes it as an 18° base angle kept within seasonal limits, with Isha also depending on twilight type. More detail follows below the list.
• Custom accepts Fajr and Isha angles from 6° to 25°, and it offers four Isha methods, explained below. Custom has no built-in Dhuhr adjustment.

Moonsighting Committee (seasonal twilight)

The tool first finds the times when the sun reaches 18° below the horizon. It then keeps Fajr and Isha within the profile’s own seasonal limits, which change through the year. On some dates, a seasonal limit sets the time rather than the sun reaching 18°. On others, the sun never reaches 18° at all. When a seasonal limit sets the time, the row is labelled Seasonal twilight, so results can differ from a plain 18° profile.

At 55°N and above, the profile first tries a time set at one seventh of the night, as Adhan 4.4.6 does. It then applies the seasonal limits, and such a row can be labelled 55°N latitude one-seventh. In the southern hemisphere, the seasonal limits follow dates shifted to match the southern seasons. The 55° one-seventh step applies only in the north.

The ordinary night-rule setting is turned off for this profile, because it uses its own seasonal limits. The profile adds 5 minutes to Dhuhr and 3 minutes to Maghrib. You can still adjust each row manually.

The Twilight type setting affects Isha in this profile. The options are General (mixed), which is the default, Ahmer (red) and Abyad (white). Twilight type is a separate choice from Standard or Hanafi Asr.

The model is described in the Adhan 4.4.6 method documentation and in the Moonsighting Committee’s own explanation. Offering this profile does not mean that every community or scholar accepts it for every place. It is also not set up to match any particular mosque.

Custom Isha options

Custom offers four Isha methods:

• Angle. Isha uses your angle and the night rule.
• Fixed interval. Isha comes a set number of whole minutes, from 30 to 180, after the chosen start point, every day. Like Umm al-Qura’s interval, it is not limited by the night rule.
• Interval on selected dates. From the first date to the last date, both included, the interval replaces the angle. It is not limited by the night rule. Outside those dates, Isha uses your angle and the night rule.
• Cap on selected dates. Inside the dates, Isha starts from your angle and night-rule result. It moves earlier only when the interval time is earlier. Otherwise, the angle or night-limit time stays as it is. The cap cannot create a time that is missing, such as where there is no sunset. Outside the dates, Isha uses your angle and the night rule.

For the two date options, choose full Gregorian dates between 1 January 2020 and 31 December 2035. The range can cross into the next year, but it does not repeat each year, so set it again for another year. Each Isha belongs to its timetable date, even when it falls after midnight. In every Isha method, Fajr uses its own angle and the night rule. These are your own settings, not any mosque’s policy.

Angles, intervals and Maghrib

An angle follows the sun, so an angle-based Isha shifts with the seasons. An interval is the same number of minutes after its start point every day. For Umm al-Qura, the interval is counted from sunset itself, not from the displayed Maghrib. The same applies to Custom’s default start point, Unadjusted sunset. In both cases, a manual Maghrib adjustment does not move Isha.

There is one exception. In Custom, you can count any interval or cap from Maghrib with adjustments instead. Then the adjusted Maghrib is the starting point, so changing Maghrib’s minutes also moves Isha. In every profile, your own Isha minutes are added last, so use Isha’s own adjustment to shift Isha by itself.

Manual adjustments of −30 to +30 minutes per row are added on top of any built-in adjustment. Calculation details in the result shows the built-in, manual and total minutes. A matching name does not prove that two calculations match. Other services define their own parameter sets and optional tuning under similar names, as the AlAdhan list of calculation methods shows. Compare the numbers rather than the label. A profile name also does not show that a government or mosque timetable uses those values.

Standard and Hanafi Asr

Asr is set by shadow length, not by a twilight angle. At solar noon an upright object casts its shortest shadow of the day, called the noon shadow. Depending on season and latitude, the noon shadow can be long or almost nothing. After noon, the shadow grows.

• Standard: Asr begins when the shadow equals the noon shadow plus one object height.
• Hanafi: Asr begins when the shadow equals the noon shadow plus two object heights.

Under the Hanafi rule the shadow has to grow further, so whenever both times can be calculated, Hanafi Asr is later than Standard Asr for the same place and date. The gap varies with date and latitude, so there is no fixed number of minutes to add. This setting changes Asr only, and Fajr, Isha and the other rows stay the same. The diagram compares both shadows from the same noon baseline. The geometry is set out in the PrayTimes prayer-time calculation reference, which explains the method but is not the library this tool uses.

Compare one setting at a time

The clearest way to see what a setting does is to change one thing and keep everything else fixed. The comparison table uses one fixed, dated example, calculated by the same engine as the tool:

• Place: Toronto, 43.6532, −79.3832
• Date and zone: 31 October 2026, America/Toronto
• Asr: Standard, except in the Hanafi row
• Night rule: one seventh of the night
• Manual adjustments: none. Rounding: nearest minute

Read the table in two steps. First, on this date, switching from ISNA 15° / 15° to FCNA Canada 13° / 13° makes Fajr later and Isha earlier, and Asr does not change. Second, keeping 15° / 15° and switching Asr from Standard to Hanafi makes Asr noticeably later, while Fajr and Isha stay where they were.

These values are reproducible calculations for that single date. They are not times for any other day, and they do not show what a Toronto mosque publishes. To run the same test for your own place, compare calculation settings in the tool.

Point: 43.6532, −79.3832. One-seventh twilight rule; zero manual adjustments; nearest-minute rounding. The named profiles retain their built-in offsets.

Adhan 4.4.6 + twilight refinement 1 + seasonal strategies 1 · IANA timezone data 2026f

High-latitude rules and missing values

The night-rule selector limits how far Fajr, and an angle-based Isha, can move into the night. It does not change the place, the timezone or the other prayers. For each calculation date, the night is measured from that date’s sunset to the following sunrise. Each of the four options takes a share of that night:

• Angle-based: the prayer’s twilight angle divided by 60. A 15° angle gives a quarter of the night.
• Middle of the night: half the night.
• One seventh of the night: one seventh.
• One-third of the night: one third.

Each option is a limit, not a replacement. An angle-based Isha can be no later than sunset plus that share. Fajr can be no earlier than the same date’s sunrise minus that share, using the same night length. If the angle time already falls inside the limit, it stays as it is.

The limit sets the time in two cases: when the sun never reaches the angle, or when the crossing falls beyond the limit. The row is then labelled Twilight rule limit.

This is a software bound. The Fajr limit reuses the night that follows the calculation date rather than measuring the night before that Fajr. A rule with the same name elsewhere may measure the night between different points, or apply at different times of year. So a matching rule name does not show a matching timetable.

Some kinds of Isha are not limited by the night rule. These include a fixed-interval Isha, such as Umm al-Qura’s, and an active date-window interval in Custom. Each stays at its interval after its start point. A date-window cap works differently: it can only make the night-rule result earlier. Fajr still follows the rule you chose. So compare an interval profile with an angle profile on a summer night. Changing the night rule can move Fajr in both, but it moves Isha only in the angle profile.

The Moonsighting Committee profile does not use this selector, which is turned off for it. Its own seasonal limits do the same job, as explained under Compare the supported profiles.

Each Fajr or Isha row shows what set its time when it is not the plain angle. The possible labels are:

• Twilight rule limit
• Seasonal twilight
• 55°N latitude one-seventh
• Fixed interval
• Date-window interval
• Date-window cap

Treat a time set by a night rule or seasonal limit as an estimate, not as a time when the sun reached the angle.

The printed month shows each row’s label, and * marks a time set by the night-rule limit. The print also lists the full settings, including any date window. A month can include dates both inside and outside a date window. For that reason, the month’s settings do not claim the window applies on every day. Check each Isha row’s label instead.

Every rule needs a sunset and a following sunrise to measure from. The seasonal limits need them too. In polar day or polar night one of these can be missing. When the sun stays very close to the horizon, the calculation may be unable to resolve a time. Night rules and seasonal limits can estimate Fajr or Isha when the sun misses the twilight angle. But they cannot replace a missing sunset or sunrise, and a date-window cap cannot create a time either. The tool then leaves the affected rows unavailable rather than borrowing another date or place. The countdown does not offer a next prayer from an incomplete day. Read more in the high-latitude calculation guidance.

Timezone, adjustments and rounding

Differences of about an hour and differences of a minute or two have different causes. Check them separately.

About an hour: the timezone

Local clock times come from the IANA time zone rules for the selected zone. These rules ship with the tool through Moment Timezone 0.6.6, using time zone data release 2026f. They cover each zone’s daylight-saving dates and historical changes, so the tool does not rely on a fixed offset such as “UTC−5”. Governments change clock rules from time to time, and the IANA time zone database is updated to match. For a typed point or your device location, your device’s timezone is offered as a convenience. It does not show which zone a remote point uses, so the tool asks you to confirm the zone.

A day off: times after midnight

On a short night, Isha can fall after local midnight. The row then shows the next day’s date, but it still belongs to the timetable date you selected. This also applies to a Custom date window: an Isha after midnight counts toward its timetable date. Check the date badge before reading a time as a day off.

A minute or two: adjustments, rounding and solar formulas

Calculation details shows the profile’s built-in adjustments and your manual minutes separately, along with the total applied to each row. For example, the Moonsighting Committee profile adds 5 minutes to Dhuhr and 3 to Maghrib before any manual minutes.

The details also show the settings behind Fajr and Isha:

• the night rule or seasonal policy in use
• the twilight type
• where any Isha interval is counted from
• any Custom date window, and whether it is active on the selected date

Each time is then rounded to the nearest minute. Calculators also use different formulas and approximations for the sun’s position. Two calculators using the same angles can therefore differ by a minute or two on some rows. Services that offer a method under the same name may also build in different margins.

Fajr and Isha need extra care on short summer nights. At that time of year the sun crosses the twilight angle at a shallow slant. A tiny difference in its calculated height can then move the crossing further than it would on other nights. That sensitivity is a reason to check the settings closely. It is not a reason to accept a large gap as normal, such as a quarter of an hour.

Sometimes the place, date, timezone and every setting are known to match, and the gap is still clearly more than a minute or two. In that case, note those settings and report a reproducible calculation issue.

What a city preset doesn’t tell the calculator

A city preset is an approximate centre point. The calculator does not account for local terrain, the exact horizon, a mosque’s precautionary margins or observation practice. If your comparison still doesn’t match, troubleshoot a time difference.

Choose a convention you can identify

If you pray with a mosque or follow a local body’s timetable, the best profile is the one that matches the convention it publishes. Ask for the details:

• the Fajr and Isha angles or interval
• where any Isha interval is counted from, and on which dates it applies
• the Asr choice
• any high-latitude rule or seasonal policy
• any adjustments

Then:

1. Choose the profile with exactly those values, if one exists.
2. Use Custom only when you know the values, including any dated Isha setting. Don’t adjust angles, intervals or dates by guesswork until the times happen to match.
3. Compare against the source’s start-time column, not its congregation times.

Three cautions apply.

First, one body’s recommendation does not describe every mosque in a country. The FCNA’s 13° recommendation for Canada, linked above, is one example.

Second, a named calculation can differ from a locally maintained timetable. The East London Mosque explains London Unified Prayer Times, which use their own dawn and dusk criteria and adjustments. Choosing Muslim World League for a London point will not reproduce that timetable.

Third, the Moonsighting Committee profile follows the Adhan 4.4.6 seasonal model. It is not a copy of any mosque’s timetable.

For two Edmonton mosques, Al Rashid and Masjid Quba Edmonton, you can view published times instead. They appear in the published mosque calendars, below the calculator on the prayer times page. Those times are copied from each mosque’s official timetable for reviewed dates from 1 June to 30 September 2026. They are historical records, not current times. They don’t show how either mosque works out its times, and no calculator profile is set up to match either mosque.

This tool can show what each convention produces, but it cannot settle which convention a community should follow. When you know the values, go back and compare calculation settings. If a gap remains, troubleshoot a time difference.