How to File California CDTFA Forms: Sales and Use Tax Return

To file a California CDTFA sales and use tax return, log in to the CDTFA online services portal at onlineservices.cdtfa.ca.gov, open your seller’s permit account, select the reporting period, and complete the CDTFA-401-A with your total sales, deductions, any purchases subject to use tax, and the resulting liability at the 7.25 percent combined state rate plus applicable district taxes.¹ You certify the return under penalty of perjury, submit, and pay in the same session. A return is required for every period, even one with zero sales.²

When Your Return Is Due

The CDTFA assigns a filing frequency based on your estimated taxable sales when you register. The three schedules work like this:

Quarterly filers cover January through March, April through June, July through September, and October through December. Each return is due by the last day of the month after the quarter closes, so the January through March return is due April 30.
Monthly filers submit by the last day of the following month.
Annual filers submit the January through December return by January 31 of the next year.

If a due date falls on a weekend or state holiday, the deadline moves to the next business day. Revenue and Taxation Code Section 6452 makes filing mandatory for every seller and every person liable for use tax.³ The CDTFA maintains a full calendar of period-by-period deadlines, including prepayment schedules that apply to larger filers.⁴

What Goes on the CDTFA-401-A

The return walks through total sales (both taxable and nontaxable), then subtracts deductions to arrive at the taxable amount. The deductions the form recognizes include:

Sales to other retailers for resale, backed by a valid CDTFA-230 resale certificate from the buyer.
Nontaxable food products, meaning most grocery items sold for home consumption.
Nontaxable labor, such as repair and installation charges billed separately.
Sales to the U.S. government.
Sales in interstate or foreign commerce.

After deductions, the form applies the combined state rate of 7.25 percent, which breaks down as a 6 percent state tax, a 0.25 percent county tax, and a 1 percent local tax. Any district taxes that apply to your location or delivery point are added on top.²

Use Tax on the Same Return

Use tax gets reported on the CDTFA-401-A alongside your sales. You owe it in two common situations: you bought tangible property from an out-of-state retailer who didn’t collect California tax, or you bought something with a resale certificate and then used it yourself instead of reselling it. Both go on the return for the period the purchase or use occurred.²

A Note on Resale Certificates

The CDTFA-230 resale certificate is what you give your suppliers so they don’t charge you tax on inventory you’ll resell. You don’t send it to the CDTFA — it stays on file with the supplier. Misusing a resale certificate to avoid tax on a personal purchase is a misdemeanor and carries a penalty of 10 percent of the tax due or $500, whichever is greater.⁵

Filing and Paying Online

Online filing is the fastest route. After logging in at onlineservices.cdtfa.ca.gov, select your account, choose the reporting period, and enter your figures. Review the calculated liability, sign electronically under penalty of perjury, and submit. The system issues a confirmation number right away. Perjury under California law carries a state prison sentence of two, three, or four years, so the certification is not a formality.⁶

Payment happens in the same session. Your options:

Bank account withdrawal, using your routing and account numbers, at no fee.
Credit card, subject to a 2.3 percent service fee charged by the processor rather than the CDTFA.
Electronic funds transfer, which is required for certain high-volume filers and must be completed by 3:00 p.m. Pacific time on the due date to count as timely.
Check or money order made payable to the California Department of Tax and Fee Administration, with your CDTFA account number written on the payment.

CDTFA offices don’t accept cash unless you’ve requested a specific exemption in advance.⁷

Paper Filing as a Backup

If you file on paper, mail the return and payment to:

California Department of Tax and Fee Administration
PO Box 942879
Sacramento, CA 94279-8062

The postmark must be on or before the due date. Electronic filing processes faster and gives you instant confirmation, so paper works best as a fallback.¹

Fixing a Return After You File

How you correct a mistake depends on which direction it went. For most errors, whether you underreported or overreported, log in to online services, select the account and period, choose Amend Return, and enter the corrected figures. The system recalculates the liability and shows any tax owed or credit due.⁸

If you overpaid and want the money refunded rather than credited to future returns, file a CDTFA-101, Claim for Refund or Credit. The form requires the period covered, the specific grounds for the refund, and supporting documentation.⁹ The CDTFA-101 is only for overpayments. If you underpaid, amend the return online and pay the difference instead.¹⁰

Penalties and Interest for Missing the Deadline

Two separate penalties can apply, and they stack:

A late return penalty of 10 percent of the tax due, charged when the return is filed after the deadline.
A late payment penalty of 10 percent of the unpaid tax, charged when payment arrives after the deadline.

If the late payment resulted from negligence or intentional disregard of the law, the penalty on prepayment deficiencies also rises to 10 percent.¹¹

Interest accrues on any unpaid balance from the original due date until it’s paid. The rate is the federal underpayment rate plus 3 percentage points and adjusts periodically. For the full year 2026, the rate is 10 percent annually.¹²

Records to Keep After You File

Keep all sales tax records for at least four years: invoices, receipts, resale certificates, exemption documents, bank statements, and sales journals. The CDTFA can audit any open period within that window, and without records the burden falls on you to prove the figures you reported were correct.¹³

1
California Department of Tax and Fee Administration. CDTFA-401-A – State, Local, and District Sales and Use Tax Return
2
California Department of Tax and Fee Administration. Instructions for Completing the CDTFA-401-A
3
California Department of Tax and Fee Administration. California Revenue and Taxation Code 6452 – Return
4
California Department of Tax and Fee Administration. Filing Dates for Sales and Use Tax Returns
5
California Department of Tax and Fee Administration. California Resale Certificate
6
Justia. California Code Penal Code 118-131 – Perjury and Subornation of Perjury
7
California Department of Tax and Fee Administration. Online Services — Make a Payment
8
California Department of Tax and Fee Administration. Filing a Claim for Refund – Required Information
9
California Department of Tax and Fee Administration. CDTFA-101 – Claim for Refund or Credit
10
California Department of Tax and Fee Administration. Filing a Claim for Refund (Publication 117)
11
California Department of Tax and Fee Administration. Regulation 1703
12
California Department of Tax and Fee Administration. Interest Rates
13
California Department of Tax and Fee Administration. Regulation 1698