Why two sites give you two different Fajrs
Dhuhr, Asr and Maghrib are tied to things anyone can see: the sun crossing the meridian, a shadow reaching a length, the sun going down. Fajr and Isha are not. They are tied to the beginning and end of twilight, and twilight has no edge — it fades.
So the authorities fixed a number instead: how many degrees below the horizon the sun must be. The Muslim World League says 18° for Fajr, ISNA says 15°, the Egyptian authority says 19.5°. That spread is twenty minutes at a British latitude in spring and can exceed half an hour at midsummer.
None of them is a mistake. They are different judgements about when dawn has begun, made by serious people, and a calculator that picked one silently would be picking a side while pretending to be neutral. This page asks.
Asr, and why it moves by an hour
Asr begins when a thing’s shadow reaches a multiple of its own length, and the schools differ on the multiple: the Hanafi school uses two, the Maliki, Shafi’i and Hanbali schools use one. Between them lies anything from forty-five minutes to an hour and a half, widening through the winter.
That is a difference between schools, not between websites. If two timetables disagree by about an hour on Asr alone, this is almost always why.
Your location does not leave your device
Most prayer time sites send your coordinates to a server, which computes the times and sends them back. This one has no server to send them to. The permission prompt is your browser’s, the coordinates stay in the tab, and the astronomy runs on your own device — the same promise every other page here makes, kept on the one page where it would have been easiest to break.
You can also type the coordinates by hand and never touch the permission. Right-clicking your street on almost any map will give them to you.
The Qibla is not the direction on a flat map
On a sphere the shortest path between two points is a great circle, and a flat map bends it. From London the Qibla is about 119° — south-east — which surprises people who expect to face a point they can put a finger on in an atlas. From New York it is roughly 58°, which is north of east: you face towards the pole, not across the Atlantic.
And the bearing here is from true north, while a phone compass reads magnetic north. The gap between them runs from a fraction of a degree to more than twenty depending where you stand. Set your compass app to true north before you turn.
Follow your mosque
The astronomy on this page is the standard algorithm and its arithmetic is checked against known values, including the Qibla bearings of five cities on four continents. That still does not make it the timetable to pray by.
A mosque’s timetable carries what a formula cannot: the horizon actually visible from your town, its altitude, the caution a community applies to Fajr in high summer, and the convention its scholars have settled on after argument. Where the two differ, the mosque is the one people pray by — and should be.