IRS Standard Mileage Rate
The IRS publishes standard mileage rates that employees, self-employed individuals or other taxpayers can use in computing the deductible costs of operating their car for business, charitable, medical or moving expense purposes.
In California, it is required that an employer reimburse an employee for the miles that the employee drives using their own car to perform the duties of their job (excluding miles driven to or back from work). When an employee’s mileage is reimbursed, it is generally reimbursed at the IRS standard “business” mileage rate.
The IRS standard “business” mileage rate is currently 56 cents per mile. This rate is effective starting January 1, 2021. The IRS typically revises this rate each year, and occasionally more often if the price of gasoline fluctuates significantly.
You can view the IRS table summarizing the various current mileage reimbursement rates and effective dates here. IRS Publication 463 (Chapter 4) has more information on deducting car expenses and using the standard mileage rates.