California estimated tax calculator, 2026.
California does not split estimated tax into four equal payments. The required annual payment is due 30% on April 15, 40% on June 15, nothing on September 15 and 30% on January 15, and the safe harbor depends on last year’s income: 100% of the 2025 tax, 110% above $150,000 of 2025 AGI, and no prior-year safe harbor at all once 2026 AGI reaches $1,000,000. Enter the 2026 tax or the figures to estimate it, the 2025 return, withholding and what has been paid. The sheet returns the required annual payment and the rule behind it, each installment, what is underpaid as of a date you choose, the FTB 5805 penalty at the 7% rate, and the balance to pay by January 15, 2027.
Rules and figures are the Franchise Tax Board’s 2026 Form 540-ES instructions and 2025 Form FTB 5805 instructions, read October 2026 and listed at the bottom.
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| Installment | Due | Share | Required | Withholding credited | Estimates paid | Cumulative short | Penalty |
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Required: the share of the required annual payment. Cumulative short: required to date less everything credited to date; a payment is applied to the earliest open installment, so a later catch-up clears earlier shortfalls. Penalty: the shortfall outstanding in each period times 7% times days over 365, from the due date to the next payment date or April 15, 2027.
The required annual payment
Worksheet line 19: the lesser of 90% of the 2026 tax and 100% of the 2025 tax, or 110% of the 2025 tax when 2025 California AGI was above $150,000 ($75,000 married or RDP filing separately). When 2026 California AGI is $1,000,000 or more ($500,000 separate) the prior year drops out and 90% of the 2026 tax is required. Farmers and fishermen use two thirds and one payment; they are not modeled here. If the 2026 tax less withholding and credits is under $500 ($250 separate), no estimates are required.
30, 40, 0, 30
Line 22 of the worksheet: after withholding, 30% of the balance is due April 15, 2026, 40% June 15, nothing September 15, and 30% January 15, 2027. Withholding counts as paid in the same proportions on the same dates unless you show otherwise. Filing the 2026 return and paying in full by January 31, 2027 replaces the fourth installment. Income that arrives unevenly can use the annualized method on FTB 5805 Schedule AI instead.
Penalty and e-pay
FTB computes the underpayment penalty itself from the return, installment by installment, at the FTB rate without compounding: 7% for the whole 2026 computation period, from each due date to the payment date or April 15, 2027. Once any estimate or extension payment exceeds $20,000, or an original return shows more than $80,000 of tax, every later payment must be electronic; a paper check afterwards costs a 1% penalty. The PTE elective tax credit reduces the owner’s estimates; the elective tax itself is outside the entity’s estimate computation.
Rules
- Franchise Tax Board, 2026 Instructions for Form 540-ES: the 30/40/0/30 installments, the $500 and $250 thresholds, the 90%, 100% and 110% rules and the $150,000 and $75,000 AGI test, the $1,000,000 and $500,000 rule, the due dates, the January 31 early-return rule, the standard deduction of $5,706 and $11,412 in the 2026 worksheet, the behavioral health services tax worksheet, mandatory e-pay at $20,000 and $80,000 with the 1% penalty. Read October 27, 2026.
- FTB, 2025 Instructions for Form FTB 5805: penalty figured separately per installment from the due date to the payment date or the return due date, withholding treated as paid in the required proportions on each due date, payments applied to the earliest underpayment, days over 365, the rate periods.
- FTB, 2025 California Tax Rate Schedules (the 540-ES worksheet uses the 2025 table for the 2026 estimate) and the 2025 Form 540 exemption credits: $153 per personal, blind and senior exemption, $475 per dependent, limited above $252,203 single, $504,411 joint and $378,310 head of household of federal AGI.
- FTB interest rate: 7% for January 1 to June 30, 2026 (set September 2025), July 1 to December 31, 2026 (February 2026) and January 1 to June 30, 2027 (September 2026); the estimate penalty uses the same rate. See the FTB interest and penalty rates article for the series.
- Dates: April 15, 2026 (Wednesday), June 15, 2026 (Monday), September 15, 2026 (Tuesday), January 15, 2027 (Friday), April 15, 2027 (Thursday). None falls on a weekend or holiday.
Simplifications
- Residents on a calendar year. Nonresidents, part-year residents, fiduciaries, farmers and fishermen, fiscal years, and the annualized income installment method are not modeled.
- The income estimate applies the 2025 rate schedule, the 2026 worksheet standard deduction, the personal and dependent exemption credits without the high-AGI limitation, and the 1% behavioral health services tax. Senior and blind exemptions, the renter’s credit and refundable credits are left out; add them under other credits.
- Estimate payments are taken as made on or before each due date in the amount entered. A late payment inside a period is not dated separately; enter it in the next column to see the penalty it stops.
- The penalty is an estimate at 7% for every day through April 15, 2027. FTB bills the exact amount after the return is filed; waivers for casualty, disaster, retirement after 62 or disability are on FTB 5805 Part I.
- This is a planning aid, not FTB’s computation and not tax advice.
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