Security Deposit Interest Calculator — Illinois
Calculate the interest you owe a Illinois tenant on their security deposit, using the state's own rule and statute.
This rate is published each year — confirm the current year's figure with the cited source before relying on it.
Interest owed to tenant
$0.41
- Time held
- 2.03 yrs
- Total to return
- $2,000.41
Illinois rule
In buildings of 25+ units, deposits held six months or more earn interest at the rate the largest IL commercial bank pays on minimum passbook savings as of Dec 31 (the IDFPR publishes it; the 2026 rate is about 0.01% APY).
Applies to: Buildings with 25 or more units.
When paid: Annually, within 30 days of the end of each 12-month period.
Last verified June 12, 2026.
Not legal advice. LandlordKit provides general informational tools, not legal advice. Landlord-tenant laws change and vary by city and county. Verify the cited statute and consult a licensed attorney before acting on any result.
How Illinois treats security deposit interest
In buildings of 25+ units, deposits held six months or more earn interest at the rate the largest IL commercial bank pays on minimum passbook savings as of Dec 31 (the IDFPR publishes it; the 2026 rate is about 0.01% APY).
Scope
Buildings with 25 or more units.When it must be paid: Annually, within 30 days of the end of each 12-month period.
Worked example
Example: a $1,500.00 deposit held for 2 years at 0.01% per year. Simple interest owed ≈ $0.30, so the landlord returns about $1,500.30 in total. (Rates can change year to year — confirm the current figure.)Last verified June 12, 2026.
Illinois security deposit obligations
Even where interest isn't required, Illinois still regulates the deposit itself: you generally must return it within 45 days (or 30 days if you're itemizing deductions) of move-out (765 ILCS 710). You must include an itemized statement of any deductions.
Open the Illinois deposit return tracker to confirm the deadline and build an itemized deductions statement.
Illinois security deposit interest FAQ
Do landlords have to pay interest on security deposits in Illinois?+
Yes. In buildings of 25+ units, deposits held six months or more earn interest at the rate the largest IL commercial bank pays on minimum passbook savings as of Dec 31 (the IDFPR publishes it; the 2026 rate is about 0.01% APY). (765 ILCS 715 (Security Deposit Interest Act)).
How is security deposit interest calculated in Illinois?+
Interest is simple (non-compounded). Multiply the deposit by the annual rate and by the number of years held. Interest only begins after the deposit has been held 6 months.
When must Illinois landlords pay the interest to the tenant?+
Annually, within 30 days of the end of each 12-month period.
Does the Illinois security deposit interest law apply to every rental?+
Not necessarily. Buildings with 25 or more units. Check the statute (765 ILCS 715 (Security Deposit Interest Act)) for the exact scope.
When must a Illinois landlord return the security deposit?+
Generally within 45 days of move-out (30 days if deductions are itemized) (765 ILCS 710). Use the LandlordKit deposit return tracker for the exact rule and an itemized statement.
Is the LandlordKit security deposit interest calculator free?+
Yes — it's completely free, requires no signup, and you can download a PDF interest statement to give your tenant.
Other states
Need the full picture? See the security deposit interest calculator for all states.