California State Tax Guide
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California State Tax Guide
Extension rules
Extension type: Automatic — no separate state request required
No form required for the extension itself. Any tax owed must still be paid by April 15 to avoid interest and penalties. Use Form FTB 3519 to submit the payment.
The California extension extends the time to file, not the time to pay. Pay the balance due by the payment deadline to avoid penalties and interest.
California Key deadlines (tax year 2025, return filed in 2026)
- Filing deadline: Apr 15, 2026
- Extension request deadline: Apr 15, 2026
- Extended return deadline: Oct 15, 2026 (6-month extension)
- Payment deadline: Apr 15, 2026
- Differs from federal: No
Interest and penalties accrue on any unpaid balance after this date, even with a valid extension.
When a deadline falls on a weekend or legal holiday, it moves to the next business day.
Estimated payments
- Apr 15, 2026
- Jun 15, 2026
- Sep 15, 2026
- Jan 15, 2027
California grants an automatic 6-month extension to file (not to pay).
Payment rules
Pay any balance due to California Franchise Tax Board (FTB) by the payment deadline. Electronic payments post fastest; include the payment voucher when paying by check.
Official payment portal
Web Pay (bank transfer) · Electronic payment
Payment options
- Web Pay (bank transfer) · Free
- Credit / debit card · Processor fee applies
- Installment agreement
- Check or money order (Form FTB 3582)
Payment plan availability
Available: Yes
Installment payment plans are available by request through California Franchise Tax Board (FTB).
Filing forms
Regular filing
- Form 540 (resident) - California individual income tax return
- Form 540NR (part-year / nonresident) - Supporting schedule or payment voucher
Extension
- Form FTB 3519 (extension payment) - Request for extension of time to file
California Refund Tracking
| Filing method | Typical processing time |
|---|---|
| E-file | up to 3 weeks |
| Paper | up to 3 months |
| Amended | Amended or manually reviewed returns take longer. |
Do I need to file?
You generally must file a California return if you are required to file a federal return and your California-source income exceeds the state's filing thresholds.
- Residents: Residents with gross income above the state filing threshold must file Form 540.
- Part-year residents: Part-year residents with California-source income during the CA period file Form 540NR.
- Nonresidents: Nonresidents with California-source income file Form 540NR.
- Self-employed individuals earning $400+ in CA must file regardless of total income.
Official filing requirements — California Franchise Tax Board (FTB)
Thresholds change annually. Confirm your situation against current California Franchise Tax Board (FTB) guidance.
Filing methods
Online filing
Residents can file electronically using approved e-file providers or tax software such as FileTax, or through California Franchise Tax Board (FTB) online services.
Recommended — e-filed returns are processed ahead of paper returns.
Mail filing
Paper returns may be mailed following California Franchise Tax Board (FTB) instructions using Form 540 (resident).
Paper returns generally process slower than e-filed returns.
