Hi Hope you can help me. I'm trying to work out what amount of money I will have available to me every month should I buy my own car whilst retaining the fuel card my company give me for personal and business miles. I am a higher rate tax payer. I get an allowance pre-tax of £375 = £225 after tax per month My current Passat (company car) costs me £130 in tax per month I think I will do 25000 miles in total per annum, 3000 of which will be personal My thinking was that I get 45p for the first 10k miles = £4500 Then I get 25p thereafter for the remaining 15k miles = £3750 Total = £8250 My estimate is that I will spend £3000 per annum on the fuel card. Do I deduct this from the £8250 then retain 60% to get my annual "rebate"? i.e. £8250 - £3000 = £5250 £5250 * 60% = £3151 per annum or £263 per month? This means I'll have £225 + £130 + £263 = £618 per month for my own vehicle? Cheers all. Sorry, I've been searching for ages to find a simple formula online but failed.