The U.S. Internal Revenue Service on Tuesday announced the 2021 rate used to calculate the deductible costs of operating a car, van, pickup or panel truck for business purposes would be 56 cents per mile, 1.5 cents lower than 2020. The deductible mileage rate is based on an annual study of the fixed and variable costs of operating an automobile. Many companies use the standard rate to calculate reimbursements for employees who use personal vehicles for business.