State estimated tax — 2026

California Estimated Tax Payments 2026

Who has to make California quarterly estimated payments, the 2026 due-date calendar, the safe-harbor rules that avoid an underpayment penalty, and how to pay through Web Pay.

Who must pay

California requires Form 540-ES payments once your projected 2026 California tax, net of credits and withholding, reaches $500 — or $250 for married-filing-separately households — and your withholding alone won’t satisfy either the 90%-of-2026 or 100%-of-2025 test below.

2026 due-date calendar

Installment	% of annual estimate	Due date	Note
Q1	30%	April 15, 2026	—
Q2	40%	June 15, 2026	—
Q3	0%	September 15, 2026	No payment is due — California folds the 3rd installment into the 4th.
Q4	30%	January 15, 2027	—

California uses an unusual 30% / 40% / 0% / 30% schedule instead of four equal 25% payments. The Franchise Tax Board’s own Form 540-ES worksheet states plainly that "there is not a required 3rd installment payment" — taxpayers who pay 25% every quarter out of habit underpay Q2 and overpay Q3, which can trigger a penalty on the June shortfall even though the annual total comes out even.

Safe harbor — avoiding the underpayment penalty

Most California taxpayers stay penalty-free by paying whichever is smaller: 90% of 2026 tax, or 100% of 2025 tax. High earners face a stricter version of that second option — once 2025 California AGI passes $150,000 (or $75,000 filing separately), the 100% figure becomes 110% instead. A second, harsher rule kicks in at the very top: 2026 California AGI of $1,000,000 or more ($500,000 filing separately) removes the prior-year option entirely, leaving only the 90%-of-actual-2026-liability path.

How to calculate your payment

Estimate your annual California tax, test it against the safe harbor above, then split the required annual payment across the installments in the calendar. The site's quarterly planner handles the math and the federal side together.

Open the quarterly estimated tax calculator → Check your underpayment penalty exposure →

How to pay

Pay online through Web Pay, or mail a check or money order with the Form 540-ES voucher. California requires electronic payment for everyone once any single estimated or extension payment exceeds $20,000, or your total tax liability for a year exceeds $80,000 — once triggered, every future payment must be electronic or a 1% noncompliance penalty applies.

Penalty basics

The FTB’s estimate-penalty rate tracks the same interest rate used for personal-income-tax under- and overpayments and adjusts semiannually under Revenue and Taxation Code §19521. The rate in effect for the second half of 2026 (July 1 – December 31) is 7%.

California-specific notes

A 1% Mental Health Services Tax (officially renamed the Behavioral Health Services Tax) applies on top of the regular brackets for taxable income over $1,000,000 — factor it into your annual estimate if you’re near that threshold.
California’s Q1 due date lines up with the federal April 15 date — there is no separate California-only Q1 deadline.
The $150,000/$75,000 high-income test looks at PRIOR-year (2025) AGI; the $1,000,000/$500,000 no-prior-year-option test looks at CURRENT-year (2026) AGI — they are two distinct rules, not the same threshold restated.

See the California 2026 tax brackets for current rates, or the California state tax calculator to estimate your full-year liability.

Frequently asked questions

When are California estimated tax payments due in 2026?

The four California due dates for 2026 are April 15, 2026, June 15, 2026, September 15, 2026, January 15, 2027. California uses an unusual 30% / 40% / 0% / 30% schedule instead of four equal 25% payments. The Franchise Tax Board’s own Form 540-ES worksheet states plainly that "there is not a required 3rd installment payment" — taxpayers who pay 25% every quarter out of habit underpay Q2 and overpay Q3, which can trigger a penalty on the June shortfall even though the annual total comes out even.

Why is California’s Q2 estimated payment 40% instead of 25%?

California’s Form 540-ES uses a front-loaded 30% / 40% / 0% / 30% schedule rather than four equal quarters. Q1 (April 15) is 30%, Q2 (June 15) is 40%, Q3 (September 15) requires no payment at all, and Q4 (January 15) is the remaining 30%. Paying a flat 25% every quarter under-pays June and can trigger a penalty on that shortfall even though nothing is owed for September.

Do I lose the prior-year safe harbor if I’m a high earner in California?

It depends which threshold you cross. If your 2025 California AGI was over $150,000 ($75,000 married filing separately), you can still use the prior-year test, but at 110% instead of 100%. If your 2026 California AGI reaches $1,000,000 ($500,000 married filing separately), the prior-year option disappears entirely and you must pay 90% of your actual 2026 tax.

When does California require electronic payment?

Once any single estimated-tax or extension payment you make exceeds $20,000, or your total tax liability for the year exceeds $80,000, the Franchise Tax Board requires all of your future payments for that and later years to be made electronically (Web Pay, credit card, or EFT) — a 1% penalty applies to noncompliant payments after the threshold is triggered.

How do I pay California estimated tax?

Pay online through Web Pay, or mail a check with the Form 540-ES voucher. California requires electronic payment for everyone once any single estimated or extension payment exceeds $20,000, or your total tax liability for a year exceeds $80,000 — once triggered, every future payment must be electronic or a 1% noncompliance penalty applies.

Estimated tax in other states

Compare how California stacks up against the other states with a Rising search trend for estimated-tax rules.