The 26 Deadlines Built Into Due Days

Federal — the corporation

Filings the S corp itself owes the IRS, including payroll forms for owner-employees.

1099-NEC to contractors + IRS

For anyone paid $600+ last year · no extensions available

FederalFeb 2

W-2s to employees + SSA

Including your own W-2 as an owner-employee

FederalFeb 2

Form 940 — annual FUTA return

Federal unemployment tax for the prior year

FederalFeb 2

Form 941 — Q4 of the prior year

Quarterly payroll tax return

FederalFeb 2

Form 1120-S + Schedule K-1s

The S corp return itself — or Form 7004 for an automatic extension

FederalMar 16

Form 941 — Q1

Quarterly payroll tax return

FederalApr 30

Form 941 — Q2

Quarterly payroll tax return

FederalJul 31

Extended Form 1120-S deadline

If you filed Form 7004 in March — final, no further extensions

FederalSep 15

Form 941 — Q3

Due Nov 2 in 2026 (Oct 31 is a Saturday)

FederalNov 2

Federal — you personally

S corp profits flow to your personal return via Schedule K-1, so your 1040 deadlines are part of the same picture.

Q4 federal estimated tax (Form 1040-ES, prior year)

Final individual installment for last year's income

FederalJan 15

Personal Form 1040

Your individual return, with the K-1 attached

FederalApr 15

Q1 federal estimated tax (Form 1040-ES)

First installment for the current year

FederalApr 15

Q2 federal estimated tax (Form 1040-ES)

Second installment

FederalJun 15

Q3 federal estimated tax (Form 1040-ES)

Third installment

FederalSep 15

California — the corporation

The FTB and Secretary of State obligations that catch most new S corp owners off guard.

CA Form 100S + pay 1.5% franchise tax balance

Filing auto-extends to Sep 15, but payment is due now

CaliforniaMar 16

Q1 CA corp estimated tax (Form 100-ES) — includes the $800 minimum

The minimum franchise tax must be covered by this installment

CaliforniaApr 15

Q2 CA corp estimated tax (Form 100-ES)

Second installment

CaliforniaJun 15

Q3 CA corp estimated tax (Form 100-ES)

Third installment

CaliforniaSep 15

Q4 CA corp estimated tax (Form 100-ES)

Corporations pay their last installment in December, not January

CaliforniaDec 15

CA Statement of Information (Form SI-550, $25)

Due by the end of your incorporation anniversary month

CaliforniaVaries

California — you personally

California weights personal estimates 30% / 40% / 0% / 30% — there's no September payment, which is exactly the kind of quirk people misremember.

Q4 CA personal estimated tax (Form 540-ES, prior year) — 30%

Final installment for last year's income

CaliforniaJan 15

Q1 CA personal estimated tax (Form 540-ES) — 30%

First installment for the current year

CaliforniaApr 15

Q2 CA personal estimated tax (Form 540-ES) — 40%

The big one — 40% of the year's estimate

CaliforniaJun 15

Corporate formalities & insurance

Not tax filings — but skipping them risks your corporate veil and coverage. Add your own custom items too: city business license, permits, anything.

Annual shareholder/board meeting #1 + minutes

Corporate formality — document it and file the minutes

CustomFeb 15

Business insurance renewal (GL + workers' comp)

Attach the new certificates when they arrive

CustomJul 1

Annual shareholder/board meeting #2 + minutes

Second of two annual meetings

CustomAug 15

Not in California? Not a problem. The federal items apply nationwide, and every California item is editable — swap in your own state's equivalents once and they recur every year through the template. Your business's obligations may differ from this list; that's what the editor is for.

Deadline guides

S Corp Tax Due Dates 2026 — the full calendar → California S Corp Deadlines 2026 → When Is Form 1120-S Due? → First-Year S Corp Checklist → Try the interactive demo →

The 26 deadlines built into Due Days

Federal — the corporation

Federal — you personally

California — the corporation

California — you personally

Corporate formalities & insurance

Deadline guides

All 26, tracked for you