California has a reputation as the strictest state in everything — so it surprises people that its resale certificate rules are among the more flexible. No mandatory state form. No expiration date. The catch sits on the other side of the ledger: if the certificate you accepted doesn't hold up, you — the seller — owe the tax. California's flexibility is generosity toward the buyer, financed by your liability. So verification matters more here, not less.
(For the state at the other end of the spectrum, see Louisiana, where the state issues the certificate itself. South Carolina sits closer to California — friendly rules, still a lookup to run.)
What counts as a California resale certificate
California's own form is the CDTFA-230 (General Resale Certificate) — but unlike many states, CA doesn't require its form. Under Regulation 1668, any document — the regulation says "such as a letter or purchase order" — qualifies as a resale certificate if it contains the essential elements: the purchaser's signature, their name and address, their seller's permit number, a description of the property, a statement that it's purchased for resale, and the date of execution. The CDTFA-230 is simply the pre-built way to get all of that right.
Three details in that list do more work than they look like they do.
The words matter. The document must contain the phrase "for resale." The regulation explicitly rejects "non-taxable," "exempt," or similar terminology as substitutes. And the property has to be described — either an itemized list, or a general description of the kind of property being bought for resale. A certificate that gestures at "various goods" is thin.
A missing permit number isn't automatically a defect — but a blank space is. Regulation 1668(b)(1)(C) calls for the number of the seller's permit held by the purchaser. If the purchaser isn't required to hold one — because they sell only property whose retail sale isn't taxable (the regulation's own example is food products for human consumption), or because they make no sales in this state — the certificate must instead carry a sufficient explanation of why no California permit is required. For an out-of-state purchaser with no California permit, CDTFA's staff guidance says the out-of-state permit number should be noted on the certificate. What none of that does is bless an empty field. Blank, with nothing offered in its place, is a defect.
California doesn't publish an official format for its permit numbers. Unlike states with a documented "nine digits, displayed 3-5-1" pattern, CDTFA specifies only that the number of the permit held by the purchaser must appear. (Permits commonly begin with letter prefixes, but there's no authoritative public mask — one of the small absurdities of this system.)
The one that catches people: the wrong CDTFA-230
A resale certificate (CDTFA-230) and a manufacturing exemption certificate (CDTFA-230-M) are different documents for different exemptions, and they are not interchangeable. A wholesale buyer handing you a 230-M for a resale purchase — or vice versa — has handed you a certificate that doesn't cover the transaction. Form-matches-exemption is a real check, not paperwork pedantry.
Verifying it: CDTFA's permit lookup
CDTFA's Online Services portal has a "Verify a Permit, License, or Account" tool (onlineservices.cdtfa.ca.gov). Enter the seller's permit number and it confirms whether the permit is valid and currently active.
As with every state lookup: this verifies the permit behind the certificate, not the certificate itself. The combination that holds up in an audit is a complete, signed certificate plus a permit that checks out — taken timely and in good faith. Both words are the regulation's, and both matter. Timely has a specific meaning here: the regulation counts a certificate as timely if it's taken any time before you bill the purchaser, within your normal billing and payment cycle, or at or before delivery. A certificate collected three years later, or accepted despite obvious red flags, loses its protection.
No expiration, which cuts both ways
A valid California resale certificate remains in effect until it's revoked in writing — no annual clock, no renewal calendar. Convenient, and quietly risky, because nothing forces a refresh. The buyer whose permit lapsed two years ago is still sitting in your files looking valid. Since the certificate never expires on its own, periodically re-running the permit lookup is how you catch that.
The multi-state form works here (as a resale certificate only)
California accepts the MTC Uniform Sales & Use Tax Certificate, with a limit stated in the form's own footnote: valid only as a resale certificate, never as an exemption certificate. A buyer using the MTC form for a resale purchase is fine; anyone presenting it for a manufacturing or other exemption is using it somewhere it doesn't work.
Keep the records
Keep the certificate four years. That's a records rule, not a statute of limitations — Regulation 1698 requires records be preserved "for a period of not less than four years" unless CDTFA authorizes destruction sooner in writing. (The assessment window is a separate question: generally three years where a return was filed, eight where none was.) The certificate, the permit-lookup result, and whatever supports an out-of-state number or a no-permit explanation all belong in the file.
The checklist version
- All Regulation 1668 elements present: signature, name and address, permit number (or out-of-state number / written explanation), property description, the phrase "for resale," date
- Right form for the exemption: CDTFA-230 for resale; a 230-M doesn't cover a resale purchase
- Run the permit through CDTFA's Verify a Permit, License, or Account lookup; save the result
- MTC form? Accepted in CA, but as a resale certificate only
- No expiration to track, so calendar a periodic permit re-check instead
- Keep everything four years
Or skip the manual pass: our free validator reads California resale certificates (CDTFA-230 and the MTC form), checks the required fields and the rules behind them, and cites the rule for anything that fails — in about fifteen seconds. Checking numbers against state-published registry data (TX & PA today) is part of our plans.
(General education, not tax advice — CDTFA or a SALT professional is the authority for your situation.)