Everything freelancers and small businesses need to know about charging late fees, interest rates, and collecting overdue invoices in Illinois.
This information is provided for general educational purposes only and does not constitute legal advice. Laws change frequently. Consult a licensed attorney in Illinois for advice on your specific situation. Last reviewed: 2026.
Usury laws cap the maximum interest rate that can be charged on overdue payments in Illinois.
9% per annum
Illinois caps interest at 9% per annum (815 ILCS 205/4). The default rate is 5%. Business loans over $5,000 are exempt from the cap.
Business loans of $5,000 or more are exempt. Banks, licensed financial institutions, and insurance companies are also exempt.
Understanding what you can and cannot charge for late payments in Illinois.
Illinois allows late fees when specified in the contract. For exempt commercial transactions (loans over $5,000), there is more flexibility.
No specific statutory cap for commercial. Consumer transactions limited by the 9% cap.
Illinois courts apply a liquidated damages analysis. The fee must be a reasonable estimate of anticipated damages.
Illinois State Prompt Payment Act sets deadlines and penalties for late payments in Illinois.
60 days after receipt of a proper invoice for state contracts (30 ILCS 540).
Interest at 1% per month on late payments from state agencies.
The Illinois State Prompt Payment Act (30 ILCS 540) requires state agencies to pay within 60 days. Interest accrues at 1% per month after that.
Certain industries in Illinois have additional rules around payment timelines, liens, and collection procedures.
Construction: Illinois Mechanics Lien Act (770 ILCS 60) requires filing within 4 months of completion for commercial projects.
Government contracts: 30 ILCS 540 mandates 60-day payment with 1% monthly interest.
Healthcare: Illinois requires prompt payment of insurance claims within 30 days of a clean claim.
Use this compliant wording on your invoices to clearly communicate your late fee policy in accordance with Illinois law.
Payment is due within 30 days of invoice date. A late fee of 1.5% per month will be applied to invoices unpaid after the due date, in compliance with Illinois law (815 ILCS 205/4, commercial exemption).
This wording works because it clearly states the rate, when it applies, and references Illinois legal standards. Always ensure your stated rate complies with Illinois's usury limits.
Practical tips for invoicing within Illinois's legal framework.
Before you can charge a late fee in Illinois, your client needs to have agreed to the terms. Include your late fee clause directly on your invoice and in your contract.
Illinois caps interest rates at 9% (statutory). Charging above this limit can void your right to collect interest entirely and may expose you to penalties.
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Compare Illinois's rules with neighboring and commonly referenced states.
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