Federal + state notes

BUSINESS TAX CALENDAR

Key federal deadlines by entity type. Filter for your structure — never miss a payment or filing.

Estimated taxes
Payroll / info returns
Business returns
C-Corp specific
Retirement / benefits
Year-end planning
January
15
Jan
Q4 Estimated tax payment dueForm 1040-ESQuarterly Est.

Fourth quarterly estimated tax payment for Sep 1 – Dec 31.

31
Jan
W-2s must be sent to employeesW-2

Distribute W-2 forms to all employees for the prior tax year.

31
Jan
1099-NEC due to contractors1099-NEC

Send Form 1099-NEC to each contractor you paid $2,000 or more last year, and file it with the IRS by the same date, on paper or electronically. (For payments made in 2025 or earlier, the threshold was $600.)

IRS page
31
Jan
W-2 copy filed with SSAW-2 Copy A

File W-2 copy A with the Social Security Administration.

February
10
Feb
Monthly payroll tax deposit (Jan)941 deposit

Monthly payroll tax deposit for January wages, if monthly depositor.

28
Feb
Most 1099s: paper IRS filing1099 + 1096 (paper)

Paper deadline for filing most Forms 1099 (not 1099-NEC) with the IRS, with Form 1096. Paper is only allowed if you file fewer than 10 information returns in the year. The electronic deadline is Mar 31.

IRS page
March
15
Mar
S-Corporation return dueForm 1120-S

S-Corp tax return or 6-month extension request due. K-1s must be issued to shareholders.

IRS page
15
Mar
Partnership return dueForm 1065

Partnership tax return or extension request due. Schedule K-1s issued to partners.

IRS page
31
Mar
Most 1099s: electronic IRS filing1099 (e-file)

Electronic deadline for filing most Forms 1099 (not 1099-NEC) with the IRS. If you file 10 or more information returns in a year, you must e-file. W-2s and 1099-NECs were due Jan 31, paper or electronic.

IRS page
April
15
Apr
Q1 Estimated tax payment dueForm 1040-ESQuarterly Est.

First quarterly estimated tax payment for Jan 1 – Mar 31. Pay if you expect to owe $1,000+.

IRS page
15
Apr
Individual return due (or extension)Form 1040

Personal income tax return. File or request 6-month extension. If extended, estimated tax still due today.

15
Apr
C-Corporation return dueForm 1120

C-Corp return or 6-month extension request due.

June
15
Jun
Q2 Estimated tax payment dueForm 1040-ESQuarterly Est.

Second quarterly estimated tax payment for Apr 1 – May 31.

15
Jun
C-Corp Q2 estimated taxForm 1120-WQuarterly Est.

C-Corporation quarterly estimated tax installment.

July
31
Jul
Form 5500 (if employer retirement plan)Form 5500

Annual report for employer-sponsored retirement plans (401k, SEP-IRA, etc.) if applicable.

September
15
Sep
Q3 Estimated tax payment dueForm 1040-ESQuarterly Est.

Third quarterly estimated tax payment for Jun 1 – Aug 31.

15
Sep
S-Corp extended return deadlineForm 1120-S

If you filed for extension in March, your S-Corp return is now due.

15
Sep
Partnership extended return deadlineForm 1065

If you filed for extension in March, your partnership return is now due.

15
Sep
C-Corp Q3 estimated taxForm 1120-WQuarterly Est.

C-Corporation third quarterly estimated tax installment.

October
1
Oct
SIMPLE IRA setup deadline (for new plans)SIMPLE IRA

To allow employees to make deferrals for the current year, a SIMPLE IRA must be established by Oct 1.

15
Oct
Extended personal return deadlineForm 1040

If you filed for extension in April, your personal return is now due. No further extensions.

15
Oct
C-Corp extended return deadlineForm 1120

If you filed for extension in April, your C-Corp return is now due.

December
31
Dec
Year-end moves deadline—

Last day to: contribute to retirement accounts, defer income, make deductible purchases, and issue final payroll.

Not tax advice. Federal deadlines shown. State deadlines vary significantly — California, New York, and Texas all have different schedules and penalty structures. If a deadline falls on a weekend or holiday, it typically moves to the next business day. Consult a CPA for your specific situation.

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