If you're an employee or a business owner who uses their personal car for business travel, you have the opportunity to claim mileage expenses.
An employee (or business owner) who uses their own car for business travel can claim mileage at the relevant amount (for a car it's currently 45p up to 10,000 miles and 25p thereafter).
HMRC say that the 45p per mile (or 25p) that you claim for using a car, not only covers petrol but it also covers wear and tear and other running costs. As well, you can claim VAT on the petrol element of the 45p/25p.
To determine the petrol element for your claims, you can refer to the advisory rates published by HMRC.
Practically speaking this would like like the following.
Presuming you have a petrol car with an engine size (cc) of up to 1,400, the advisory fuel rate is 12p.
The formula would be as following
Advisory fuel rate * number of miles = £X (inclusive of standard rated VAT)
(45p less advisory fuel rate) * number of miles = £X (Inclusive of no VAT)
Remember to keep accurate records of your journeys and please reach out to our dedicated support team if you have any further questions on this topic.