Do you attach a W-2 to your California tax return? Only if you’re filing on paper. The Franchise Tax Board (FTB) instructions for Form 540 tell paper filers to attach every W-2, W-2G, 1099, 592-B, and 593 that shows California withholding to the lower front page of the return.1State of California Franchise Tax Board. 2025 Instructions for Form 540 California Resident Income Tax Return If you e-file, your software sends the wage and withholding data electronically and nothing physical needs to go to the FTB.
Attaching the W-2 to a Paper Return
Use Copy 2 of your W-2. That’s the copy labeled for state and local tax filing. Place it on the lower front page of Form 540, along with any other forms that show California income tax withheld.1State of California Franchise Tax Board. 2025 Instructions for Form 540 California Resident Income Tax Return
The FTB also specifies how to assemble the rest of the return. Enclose your payment, if any, without stapling it. Attach the withholding forms to the lower front page. Stack all six sides of Form 540 in numerical order. Any California schedules go behind Form 540, and a copy of your federal return goes behind the schedules.1State of California Franchise Tax Board. 2025 Instructions for Form 540 California Resident Income Tax Return
Why E-Filers Don’t Attach Anything
When you e-file, your software transmits the key fields from your W-2 — the employer identification number, total wages, and California tax withheld — directly to the FTB. The FTB verifies the numbers by matching them against the wage and withholding records employers report to the California Employment Development Department.2Employment Development Department. California State Payroll Taxes – Overview That cross-check does the work the physical form would do on a paper return. Keep your W-2 in your own files, but don’t mail it in.
If You Forgot to Attach Your W-2
If you already mailed a paper return without the W-2, don’t send it in separately and don’t mail a second copy of the return. The FTB’s instructions say to wait for them to request the missing documents.1State of California Franchise Tax Board. 2025 Instructions for Form 540 California Resident Income Tax Return Unsolicited paperwork can create more confusion than it fixes, because the processing system isn’t built to match loose W-2s to returns already in the queue.
If Your W-2 Is Missing or Wrong
Employers must deliver W-2s to employees by January 31.3Social Security Administration. Deadline Dates to File W-2s If yours hasn’t shown up by mid-February, ask your employer or payroll provider for a reissue. Some charge a small duplicate fee.
If the employer won’t cooperate, call the IRS at 800-829-1040. The IRS will send the employer a letter requiring a corrected W-2 within ten days and will send you Form 4852, the federal substitute.4Internal Revenue Service. W-2 – Additional, Incorrect, Lost, Non-Receipt, Omitted The FTB’s own Form 3525 instructions point to the same IRS phone number for help after February.5State of California Franchise Tax Board. 2025 California Form 3525 Substitute for Form W-2, Wage and Tax Statement
For the California side, if the filing deadline is close and the W-2 still hasn’t arrived, use FTB Form 3525 as a substitute. You fill in your best estimate of wages and withholding based on your final pay stub and explain what you did to try to get the real W-2.5State of California Franchise Tax Board. 2025 California Form 3525 Substitute for Form W-2, Wage and Tax Statement Attach Form 3525 to Form 540, 540 2EZ, or 540NR in the same spot where the W-2 would go. Estimated figures can slow down refund processing while the FTB verifies them.
If the real W-2 eventually arrives and the numbers differ from your estimate, file an amended California return using Schedule X attached to a corrected Form 540.6State of California Franchise Tax Board. 2024 Instructions for Schedule X California Explanation of Amended Return Changes