Can I claim mileage for using my own car for business?

Yes, if you use your own car for business journeys you can use HMRC's simplified mileage rates rather than tracking actual running costs, claiming a set rate per mile for the first 10,000 business miles in a tax year and a lower rate per mile after that. This covers fuel, insurance, servicing and wear and tear, so you can't also claim these costs separately if you use the mileage method. Commuting from home to a regular, permanent workplace generally doesn't count as business mileage, but travel to client sites or temporary workplaces usually does.