To comply with I r s regulations a taxpayer's mileage log must contain : Nothing a mileage log is not needed. Taxpayers may use an average of business miles permanent to calculate the expense deduction. Dates the vehicle was used for business total miles The vehicle was driven the entire year for all purposes. Date the vehicle was used for business, purpose of the trip, estimated miles traveled for business, Estimated miles traveled for commuting, estimated total miles the vehicle was driven the entire year for all purposes. Dates the vehicle was used for business, Including date placed in service, Purpose of the trip, Miles traveled for business, Miles traveled for commuting, Total miles the vehicle was driven the entire year for all purposes, I'm destination of business travel.