Illinois Mileage Reimbursement Law
Illinois employers must reimburse necessary work expenses, including qualifying business driving. There is no single statewide cents-per-mile rate for private employers.
Short answer
Submit qualifying business mileage with supporting records within 30 calendar days of the expense, unless your employer’s written policy gives you longer. The IRS mileage rate is a benchmark, not a mandatory Illinois reimbursement rate.
At a glance
- Keep a mileage log showing the date, route, distance, and business purpose.
- Check your employer’s written policy for authorization, rates, and submission requirements.
- Keep ordinary home-to-work commuting separate from business trips.
When must an employer reimburse mileage?
Under 820 ILCS 115/9.5, necessary expenses must relate to your job and primarily benefit your employer. Required travel between work sites or to a client can qualify; the circumstances and employer’s policy matter.
Follow a lawful written expense policy. The statute addresses expenses the employer authorized or required, and permits reasonable policy limits, but not a policy that provides no reimbursement or only a token amount.
What mileage rate should I use?
Use your employer’s reimbursement method. Illinois does not prescribe one cents-per-mile rate for all private employers. If the policy uses the IRS rate, select the year and period of the trip in the calculator.
An IRS-rate estimate is not a determination of what your employer legally owes. A lower rate is not automatically unlawful; the necessary expenses and lawful policy limits still matter.
How to submit your mileage claim
- Log each trip’s date, start and end points, business purpose, and miles.
- Apply the employer’s rate or expense method and attach the log to your reimbursement form.
- Submit within 30 calendar days after the expense, or the longer period allowed by a written policy.
- Keep a copy of the request, supporting records, and employer’s response.
Missing receipts or a denied claim?
If supporting receipts do not exist or are missing or lost, Section 9.5 allows a signed statement about them. Explain the missing documentation and include the trip records you have.
If an expense should have been reimbursed and your employer refuses or does not respond, Illinois rule 300.540 allows you to seek reimbursement through a claim with the Illinois Department of Labor. Keep the policy, mileage log, submitted request, and any denial. The official filing guidance is linked below.
Official references
Common questions
Is the IRS mileage rate mandatory in Illinois?
No. It is a benchmark some employers choose. Illinois reimbursement obligations depend on necessary work expenses and lawful expense policies.
What if my employer gives me more than 30 days to submit?
A written expense policy can extend the 30-calendar-day submission period. Keep a copy of that policy and submit within its deadline.
Continue with tools
Calculate estimated reimbursement, review official rate tables, or download log templates.