A common mistake is to measure a trip from your house, or to start shortening as soon as you set off. All the schools agree that you become a traveller only once you have left your town, and that the qualifying distance is counted from that point.
The Sunni schools: leaving the built-up area
For the four Sunni madhahib, you start shortening once you pass the last buildings of your town. The detail differs a little:
- Hanafi: once you pass the populated area, including suburbs joined to it. Separate villages nearby do not count as part of your town.
- Shafi'i: once you pass the town wall or, where there is none, the last buildings.
- Maliki: once you pass the buildings and the gardens attached to them.
- Hanbali: once you pass the inhabited houses of your town.
The same rule works in reverse. On the way home, you stay a traveller until you re-enter your town's built-up area.
The Shia position: hadd al-tarakhkhus
In Ja'fari fiqh the distance of 8 farsakh is measured from the end of your town. But a traveller does not start shortening straight away. They must first pass the hadd al-tarakhkhus, the point where the town's adhan can no longer be heard, and according to many maraji' where its walls can no longer be seen, under normal conditions. Praying before that point, you still pray in full.
Modern cities and sprawl
Today's cities rarely end at a wall. Contemporary scholars generally take the edge of the continuous built-up area, including new districts that have merged with the city. A large metropolis can therefore stretch many kilometres from its centre. Measuring from your home instead of the edge can overstate the distance by 20 km or more.
How the calculator measures it
The calculator loads your town's boundary from OpenStreetMap and follows the route from your starting point. It finds the last point where the route is inside the boundary and counts only the distance after that. On the map, the saffron dot shows where you leave town and a second marker shows where your school's travel distance is reached.
Check your own route in the qasr calculator.