The Internal Revenue Service has increased the business mileage reimbursement rate to 54.5 cents from 53.5 cents for 2018. The new rate will go into effect on Jan. 1.

The I.R.S. also increased the rate for medical or moving purposes 1 cent to 18 cents. The rate for miles drive in service of charitable organizations remains at 14 cents per mile, the agency announced on Dec. 14.

A year ago, the I.R.S. reduced the reimbursement rate 0.5 cents.

The standard mileage rate for business is based on an annual study of the fixed and variable costs of operating a vehicle. The rate for medical and moving purposes is based on the variable costs. Taxpayers always have the option of calculating the actual costs of using their vehicle rather than using the standard mileage rates, according the agency.