How does a Illinois landlord calculate a legal rent increase?
Illinois has no statewide cap, so the calculation is simpler: choose the new rent (any amount), serve the proper advance notice (Lease-based; 735 ILCS 5/9-207 (30-day month-to-month termination default)), and the new rent is legal on the effective date. Local rent-control ordinances in specific cities may add a cap; check before raising rent.
Source: Lease-based; 735 ILCS 5/9-207 (30-day month-to-month termination default)
This is an informational answer based on Lease-based; 735 ILCS 5/9-207 (30-day month-to-month termination default) as of early 2026. It is not legal advice. Housing law changes year to year and local ordinances (especially in rent-controlled or rent-stabilized cities) can override or add to state law. For contested cases, consult a Illinois-licensed attorney.