Illinois Calculateur de Penalites de Retard
Calculate late fees for Illinois invoices using state-specific rules, maximum rates, and grace periods.
IL Quick Facts
Applicable Statutes
- 815 ILCS 205/4 (written contract rate)
- 815 ILCS 205/1 (default rate)
- 815 ILCS 205/4.1a (commercial exemptions)
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Illinois Late Fee Rules
Illinois sets statutory rates of 9%/year on written contracts and 5% otherwise, but the bigger story for invoices is the broad commercial exemption under 815 ILCS 205/4.1a, which frees most B2B transactions from those caps.
Statutory maximum is 9%/year on written contracts, 5% without.
Most B2B commercial transactions are exempt from these caps.
No specific late fee legislation for commercial invoices.
The Prompt Payment Act (government payments) provides 1%/month after 90 days.
Worked Example: Illinois Late Fee
On a $2,000 invoice 30 days late at the common 1.5%/month, the late fee is $30. Because most commercial accounts are exempt from the 9%/5% caps, that 18% annualized rate is widely used in Illinois B2B contracts.
Important Note
Illinois caps of 9%/5% have broad exemptions for commercial transactions under 815 ILCS 205/4.1a. Most B2B invoices are exempt.
This information is for general educational purposes only and does not constitute legal advice. Illinois laws may change. Consult a licensed attorney in your state for advice specific to your situation.
Illinois Late Fee FAQs
What is the maximum late fee allowed in Illinois?
In Illinois (IL), the maximum late fee is: No statutory cap; must be reasonable. The maximum interest rate is 9% per year (written contracts); 5% (no written contract); commercial exemptions apply. Always include late fee terms in your contracts before invoicing.
Is there a grace period for late fees in Illinois?
Illinois grace period: No statutory grace period for commercial invoices. Check your specific contract terms and applicable IL statutes for details.
What is the most common late fee rate used in Illinois?
The most common late fee rate for commercial invoices in Illinois is 1.5% per month. Illinois caps of 9%/5% have broad exemptions for commercial transactions under 815 ILCS 205/4.1a. Most B2B invoices are exempt.
Which Illinois statutes govern late fees on invoices?
The key Illinois statutes governing late fees and interest on invoices are:
- 815 ILCS 205/4 (written contract rate)
- 815 ILCS 205/1 (default rate)
- 815 ILCS 205/4.1a (commercial exemptions)
Consult a IL attorney for advice specific to your situation.
Can I charge interest on overdue invoices in Illinois?
Yes. Although the headline rates are 9% (written) and 5% (no contract), most business-to-business invoices qualify for the commercial exemption, so contractually agreed rates like 1.5%/month are routinely enforced.
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