This is compensation for missing Salah or a fast for a person who cannot perform them due to being terminally/extremely ill (old or young), unable to fast due to old age, those in need of medication if their well being maybe affected or being deceased (in which case it is given out of a third of the wealth) or in the event of a person making a minor mistake during Hajj.
The amount for each missed Salah or fast, or each minor mistake in Hajj is to give 1.6kg of wheat or its value (i.e. the same amount given for Sadaqah al-Fitr which is currently £2.50 per person) to the poor.
Fidyah is generally Sadaqah Wajibah (compulsory charity). Sadaqah Nafilah (optional charity) may be given in addition either from the deceased’s estate or on their behalf in which case both the giver and the deceased are rewarded.
Fidya is £2.50 per person For 2018