The World Federation One Stop Fiqh

Ruling 1345

A traveller who knows that he must perform qaṣr prayers but does not know some of its details – for example, he does not know that qaṣr prayers must be performed on an eight farsakh journey – then, in the event that he performs tamām prayers and realises this within the prescribed time for the prayer, he must, based on obligatory precaution, perform it again; and if he does not perform it again, he must make it up. However, if he realises after the time has expired, there is no obligation to make it up.