How company car Benefit-in-Kind tax works
A company car available for private use is normally a taxable benefit. The taxable value is based on the car's P11D value and Benefit-in-Kind percentage, with Income Tax charged on that value.
P11D value and BIK percentage
P11D value is broadly the car's list price including relevant options rather than its current used value. The BIK percentage depends on factors such as carbon dioxide emissions and fuel type, so it should be checked against HMRC tables.
Other company car costs
Private fuel provided by an employer can create a separate fuel benefit charge. Employee capital contributions, periods when the car is unavailable and salary sacrifice arrangements can also affect the final tax position.