Statute of Limitations for Unjust Enrichment / Restitution in Illinois

5 min read

Published April 8, 2026 • By DocketMath Team

This article is for informational purposes only and does not constitute legal advice. Laws change frequently — verify all citations with current official sources.

Overview

Run this scenario in DocketMath using the Statute Of Limitations calculator.

In Illinois, the statute of limitations (SOL) for unjust enrichment / restitution claims is generally 5 years, using the state’s general catchall limitations period in 720 ILCS 5/3-6.

Unjust enrichment and restitution claims often don’t map cleanly onto a single, named statutory “cause of action” with its own special limitations clock. In Illinois practice, unjust enrichment is commonly treated as an equitable-style claim, and courts may rely on the general civil limitations framework for timing. Based on the jurisdiction data provided, this guidance uses the default/general rule—not a claim-type-specific SOL—because no claim-type-specific sub-rule was found for unjust enrichment/restition in Illinois for this purpose.

DocketMath’s statute-of-limitations calculator helps you model the timing by converting your selected input dates into an estimated outside deadline.

Note: DocketMath helps you calculate deadlines; it doesn’t determine whether your specific facts satisfy the elements of unjust enrichment or restitution. For case-specific questions, review the facts carefully and consider legal counsel.

To get started right away, use the tool at /tools/statute-of-limitations.

Limitation period

Illinois’ general SOL period is 5 years for civil claims that do not fit into a more specific limitations category. For this guidance, that general period is tied to 720 ILCS 5/3-6.

What “5 years” means in practice

When a limitations period is 5 years, the basic structure is:

Choose an accrual date (the date you believe the claim “accrued” under your legal theory).
Add 5 years to that accrual date.
The claim is generally time-barred after the computed deadline, unless an exception (such as tolling) applies.

What you may need to decide: the “accrual date”

For unjust enrichment/restitution, parties frequently disagree about when the claim accrued. Common theories include:

When the defendant received the benefit
When the plaintiff discovered relevant facts
When the obligation to return the benefit became sufficiently clear

Because unjust enrichment timing can be fact-sensitive, your chosen accrual date is often the biggest driver of the result. DocketMath lets you test different accrual dates so you can see how the timeline shifts.

No claim-type-specific sub-rule found (important)

This page intentionally relies on the general/default period. Per the provided jurisdiction data:

No claim-type-specific sub-rule was found for unjust enrichment/restition in Illinois.
Therefore, the 5-year general SOL is the rule used for the calculator guidance on this page.
In other words, don’t assume there’s a shorter (or longer) special SOL for unjust enrichment/restitution here based on the data provided.

Key exceptions

Even when the default is 5 years, the practical limitations analysis can change due to exceptions—particularly tolling (pauses or interruptions of the clock) and disputes about accrual timing.

Common categories that may affect deadlines

Tolling (pauses)
Some events can pause the SOL clock. If tolling applies, the computed deadline may move later than the “accrual date + 5 years” baseline.
Accrual disputes (the clock-start issue)
If parties disagree about when the claim accrued, the deadline changes because the start date changes—even if there is no formal tolling event.
Equitable considerations (limited scope)
Unjust enrichment/restitution is often discussed in equitable terms. However, Illinois still generally uses statutory limitations principles; “equity” typically does not automatically override the SOL. Instead, equitable arguments may surface indirectly—often through accrual or tolling analyses—depending on the facts.

Practical takeaway for dossier-building

When preparing an SOL estimate for unjust enrichment/restitution in Illinois, gather:

The timeline of the benefit (when the defendant obtained/received/retained the benefit)
The timeline of the plaintiff’s knowledge (if your accrual theory depends on discovery or awareness)
Any facts that could support tolling or a legally recognized delay in running time

Pitfall: Don’t rely only on the “5 years” headline. If you pick the wrong accrual date or miss a potentially applicable tolling circumstance, your deadline estimate can be significantly off.

Statute citation

This guidance uses the general civil limitations period:

720 ILCS 5/3-6 — 5 years (general/catchall civil limitations period)

Source (Illinois General Assembly):
https://ilga.gov/ftp/Public%20Acts/101/101-0130.htm?utm_source=openai

Because the jurisdiction data indicates no claim-type-specific sub-rule was found, the default approach is to apply the 720 ILCS 5/3-6 general 5-year period.

Use the calculator

Use DocketMath’s statute-of-limitations calculator to compute a 5-year deadline based on the dates you select under the default rule used here.

Where to start

Open the calculator: /tools/statute-of-limitations

What to enter (conceptually)

The core input is your selected accrual date—the date you believe the unjust enrichment/restitution claim accrued. Depending on the calculator interface, you may also model tolling or other deadline adjustments by entering relevant dates or modifiers.

How the output changes when inputs change

If you change…	The deadline will…	Why
Accrual date moves later	Move later	The 5-year clock starts later
Accrual date moves earlier	Move earlier	Less time between accrual and deadline
You add a tolling period	Move later	Tolling pauses the clock (if supported)
You remove a tolling assumption	Move earlier	Clock resumes sooner

Checklist before you run scenarios

If you’re unsure which accrual date is most conservative, run multiple scenarios (e.g., one based on benefit receipt and another based on the latest plausible accrual/discovery theory) and compare the deadlines.