California layers a franchise tax regime on top of income tax: the $800 minimum franchise tax, LLC gross-receipts fees, an elective pass-through entity tax (PTET), and unusually weighted estimated payments. CPAs advising California clients have to track all four, and the extension rules differ by entity type.
California Tax Deadlines at a Glance (2026)
Entity Type | Return Due | Extended Due Date |
|---|---|---|
Individuals | April 15, 2026 | October 15, 2026 (automatic, no form) |
C Corporations | April 15, 2026 | October 15, 2026 (7-month) |
S Corporations | March 16, 2026 | September 15, 2026 (6-month) |
Partnerships / LLCs | March 16, 2026 | October 15, 2026 (7-month) |
A common error is grouping S corporations and partnerships under one extension date. They differ: S corporations extend to September 15 (6-month), while partnerships and LLCs taxed as partnerships extend to October 15 (7-month). California grants these extensions automatically — no form is filed — but an extension to file is never an extension to pay. Balances are due by the original date.
The $800 Minimum Franchise Tax and LLC Fees
Every corporation and LLC doing business in California owes the $800 annual minimum tax. New corporations are exempt in their first taxable year, and the 15-day rule spares entities that did no business and existed 15 days or fewer. LLCs owe an additional gross-receipts fee once total California income reaches $250,000, paid via Form 3536:
California Total Income | LLC Fee |
|---|---|
$250,000 – $499,999 | $900 |
$500,000 – $999,999 | $2,500 |
$1,000,000 – $4,999,999 | $6,000 |
$5,000,000 or more | $11,790 |
Pass-Through Entity Elective Tax (PTET)
California’s PTET (AB 150, extended through 2030 by SB 132) lets qualifying partnerships and S corporations pay a 9.3% entity-level tax, giving owners a credit that works around the federal SALT cap. For the 2026 tax year, the first PTET payment is due June 15, 2026 — the greater of $1,000 or 50% of the prior-year PTET. Missing or underpaying it doesn’t void the election, but it reduces the owner’s credit.
Estimated Payments and Penalties
California individual estimated payments follow an unusual 30% / 40% / 0% / 30% weighting across the April 15, June 15, September 15 (no payment), and January 15 installments. The late-filing penalty is 5% per month (max 25%); the late-payment penalty is 0.5% per month. The underpayment interest rate is 7% for the period through June 30, 2026.
CPA Action Steps
Confirm entity type early — the extension clock differs for S corps (6-month) vs partnerships (7-month)
Budget the $800 minimum plus any LLC gross-receipts fee tier
Calendar the June 15, 2026 PTET prepayment for electing clients
Apply the 30/40/0/30 estimate weighting, not even quarters
Verify current figures against the California Franchise Tax Board (ftb.ca.gov) before filing; rates and thresholds are updated periodically.