Illinois Mileage Reimbursement 2026: 30-Day Window

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.

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, pick the period of the trip: the federal figure is 72.5 cents per mile through June 30, 2026 and 76 cents per mile from July 1.

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.

• 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.

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.

The statutory steps behind an Illinois mileage claim.

The IRS has not published a standard mileage rate for 2027. Until it does, two things decide what a trip pays: the year you drove it and the date within that year. A 2026 trip pays 72.5 cents per mile through June 30 and 76 cents per mile from July 1. Miles driven from January 1, 2027 will use whatever figure the IRS publishes next.

The next year's rate has arrived in December in each of the last nine years, between December 14 and December 31. An announcement is not always the last word. The IRS raised the 2026 figure on July 1, halfway through the year, so a 2027 claim may need two rate periods.

A state that publishes a rate for its own travelers follows its own calendar, so it can publish the next period before the IRS does. A private employer's rate changes when its own policy changes, or when the benchmark that policy follows moves. It does not change because the calendar year turns.