HMRC Total Expenses Paid Calculator
Use this calculator to determine the total expenses paid by your employer & HMRC for business travel.
This can be useful in determining if it is wortwhile using your personal car for business purposes (as sometimes the allowance from your employer may not even cover your fuel costs).
Additionally it's worth consdiering that if your employer is not paying the maximum approved HMRC allowance, you may claim the difference as tax relief - this is known as the Mileage Allowance Relief (MAR)
Consider too that the "profit" shown here is only taking into accunt fuel costs, wear & tear, servicing, tyres, depreciation etc. are not factored in.