California tax deadlines in 2026: filing dates and estimated payments
Deadlines that fall in calendar 2026: the 2025 return and the 2026 estimated payments. Different year? See California 2025 →
California deadlines in 2026
| 2025 individual return due | April 15, 2026 |
|---|---|
| Extended filing deadline | October 15, 2026 |
| Payment due | April 15, 2026, extension or not |
| Final 2025 estimated payment | January 15, 2026 |
| 2026 estimated payments | April 15, 2026 · June 15, 2026 · September 15, 2026 · January 15, 2027 |
Conforms to April 15 with an automatic extension to October 15. Estimated installments are weighted unusually: 30% by April 15, 40% by June 15, 0% by September 15, 30% by January 15.
California estimated tax payments in 2026
You expect to owe at least $500 ($250 if married/RDP filing separately) and expect withholding and credits to be less than the smaller of 90% of current-year tax or 100% of prior-year tax.
| Q1 (2026 tax year) | April 15, 2026 |
|---|---|
| Q2 (2026 tax year) | June 15, 2026 |
| Q3 (2026 tax year) | September 15, 2026 |
| Q4 (2026 tax year) | January 15, 2027 |
| Voucher | Form 540-ES |
| Underpayment safe harbor | Pay the smaller of 90% of current-year tax or 100% of prior-year tax (including AMT); if prior-year California AGI exceeds $150,000 ($75,000 MFS) use 110% of prior-year tax instead of 100%; if current-year California AGI is $1,000,000 or more ($500,000 MFS) you must pay 90% of current-year tax. |
| Pay online | ftb.ca.gov |
California installments are NOT equal: 30% due April 15, 2026; 40% due June 15, 2026; 0% due September 15, 2026; 30% due January 15, 2027. The 110% limit on using prior-year tax does not apply to farmers or fishermen. FTB page (last updated 01/21/2026) still shows stale text in the mailing instructions ('Write ... 2024 Form 540-ES'); use the 2026 540-ES vouchers. Pay via FTB Web Pay; MyFTB shows payments already made.
Source: ftb.ca.gov, read September 3, 2026. “Payment Amount Due date 1 30% April 15, 2026 2 40% June 15, 2026 3 0% September 15, 2026 4 30% January 15, 2027”
All 51 jurisdictions in one table: state estimated tax payment dates for 2026.
California extensions
Every state's rule in one table: which states accept the federal extension in 2026.
| Does California accept the federal extension? | Not needed. The state extends everyone automatically. |
|---|---|
| Original due date | April 15, 2026 |
| Extended due date | October 15, 2026 |
| Payment | Still due April 15, 2026. The extension is to file, not to pay. An extension to file is not an extension to pay; pay by April 15, 2026 to avoid penalties and interest. |
| How to get it | Nothing to file; if you owe, pay electronically or mail Payment for Automatic Extension for Individuals (FTB 3519) by April 15, 2026. |
FTB 3519 is a payment voucher, not an extension request; the extension does not depend on the federal Form 4868.
Source: ftb.ca.gov, read September 3, 2026. “No application is required for an extension to file. ... We give you an automatic 6-month extension to file your return.”
Federal deadlines in 2026
| 2025 Form 1040 | April 15, 2026 · extension October 15, 2026 |
|---|---|
| 2025 S-corp (1120-S) & partnership (1065) | March 16, 2026 |
| 2025 C-corp (Form 1120) | April 15, 2026 |
| 2026 federal estimated payments (1040-ES) | April 15, 2026 · June 15, 2026 · September 15, 2026 · January 15, 2027 |
Source: IRS Publication 509 and Form 1040-ES instructions, irs.gov.
Frequently asked questions
When are California state taxes due in 2026?
Your 2025 California individual income tax return is due April 15, 2026. If that date falls on a weekend or legal holiday, the deadline moves to the next business day. An extension moves the filing deadline to October 15, 2026, but any tax owed is still due on the original date.
When are California estimated tax payments due in 2026?
California estimated payments for the 2026 tax year are due April 15, 2026, June 15, 2026, September 15, 2026, January 15, 2027. Use Form 540-ES or pay online. The final installment for 2025 was due January 15, 2026.
Does California accept the federal extension?
Not needed. The state extends everyone automatically. The extended filing deadline is October 15, 2026, and tax is still due by April 15, 2026.
Does a California extension give me more time to pay?
No. An extension extends the time to file, not to pay. To avoid penalties and interest, pay what you expect to owe by April 15, 2026.
Dates are the statutory deadlines that fall in 2026 and move to the next business day when they land on a weekend or holiday. Each section links to the source it was checked against. Always confirm with the California tax agency or the IRS before relying on a date. This is general information, not tax advice.