I am a member of the military and I am given an amount of money to commute between where I live at home and where I work, known as Get You Home (Travel), abbreviated to GYH (T). As this (for me) qualifies as a temporary workplace under the 24 month rule, I can claim tax relief on the mileage. It is designed so it "approximately equates to 24 journeys per annum, paid on a daily basis". The rate the military pays is based on distance, however it is paid per day rather than per mile of the journey and also assumes that I only travel once a fortnight. How do I calculate the amount I can claim back? Would I/am I allowed to calculate how often I travel (a return journey each week) and calculate the total mileage for that, work this out against the relevant rate (£0.45/£0.25, depending if the first 10,000 miles or if more), and then subtract the total amount of the allowance I have received from this amount to get the claimable amount?