Calculation method

Fixed Isha Angle Interval

The Fixed Isha Angle Interval method places Fajr when the sun is 19.5° below the horizon and Isha 90 minutes after Maghrib. Maghrib is at sunset. It is conventionally used in settings where Isha is fixed at 90 minutes after Maghrib.

Fajr angle19.5°
Maghribat sunset
Isha90 minutes after Maghrib
Used insettings where Isha is fixed at 90 minutes after Maghrib

What does the Fajr angle mean?

Fajr begins at true dawn, when the first light appears along the horizon. Astronomically that is expressed as the sun being a set number of degrees below the horizon — here 19.5°. A larger angle means an earlier Fajr.

How this method differs from the others

All nineteen methods agree on Dhuhr, Asr and Maghrib, because those are fixed by the sun's position and by shadow length rather than by convention. They differ only on Fajr and Isha, which begin when the sun sits a set number of degrees below the horizon — and that number is a judgement about when dawn first appears and when the last light leaves. Fixed Isha uses 19.5° for Fajr. A larger angle means an earlier Fajr and a later Isha; a smaller one, the reverse. Between the widest and narrowest methods the difference can reach half an hour at temperate latitudes, and more in summer further north.

Should you use it?

Use the method your local mosque or national authority uses. Praying in step with the congregation around you matters more than matching any particular calculation, and a method is a convention adopted by a body rather than a fact to be got right. Fixed Isha is the convention in settings where Isha is fixed at 90 minutes after Maghrib. If you are elsewhere, your local authority's choice is the one to follow.

Common questions

What Fajr angle does Fixed Isha use?

Fixed Isha places Fajr when the sun is 19.5° below the horizon.

When does Isha begin under Fixed Isha?

Isha is 90 minutes after Maghrib.

Where is Fixed Isha used?

It is the conventional method in settings where Isha is fixed at 90 minutes after Maghrib.

See it applied

Calculate for your own location · How prayer times are calculated

The other calculation methods

Methods differ only in the Fajr and Isha angles; every other prayer follows from the sun directly. The angle each one uses is given below.

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