Illinois · Resale certificate rules
Does Illinois accept an out-of-state resale certificate?
Yes
A certificate carrying a permit number issued by another state can support an exempt sale into Illinois. The rest of the form still has to be complete and current.
The rules we hold for Illinois
- Out-of-state certificate accepted
- Yes
- Multistate Tax Commission form accepted
- Yes
- Streamlined Sales Tax member
- No
- Certificate expiry
- 36 months
- Penalty rate on an assessment
- 20% 35 ILCS 735/3-5
- Self-collecting local jurisdictions
- Yes
Last reviewed 2026-08-31. Rules change; verify against the state before relying on this for a filing.
What does a Illinois permit number have to look like?
Every certificate claiming exemption in Illinois is matched against this pattern:
^\d{4}-\d{4}$ Format is one of eight checks, not the whole of validation. A number in the right shape belonging to a permit that has been revoked still fails, and so does a form that is correctly numbered but unsigned, undated, or missing the reason for the exemption.
What this costs at audit
An auditor does not review every exempt sale. Under statute they examine a narrow test period, calculate the share of exempt sales without a valid certificate, and apply that error rate to your total exempt sales across the whole audit period (Tex. Tax Code § 111.0042; Cal. Rev. & Tax. Code § 6481). One wrong form in a sampled quarter becomes an assessment across years.
Producing the certificate afterwards is narrower than it sounds. Streamlined states allow 120 days after a request, Texas allows 90 days from written notice, and California will not treat a certificate obtained after billing as timely at all. Certificates have been disallowed for lateness alone, with buyers who were genuinely exempt.
See what you would owe in Illinois
Upload an export of your exempt sales and we will estimate the tax, penalty and interest state by state, using the rules above. No account needed, and your file is never saved.
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