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Guide

2027 Tax Filing Deadlines for CPA Firms

Federal filing deadlines for calendar year returns in 2027, adjusted for weekends, from W-2s and 1099s through extended returns.

Last reviewed 14 September 2026

Dates below are for calendar year filers. When a deadline falls on a Saturday, Sunday or legal holiday it moves to the next business day, and that adjustment is already made here. Disaster relief can postpone deadlines for taxpayers in affected areas, so always check current IRS announcements.

DateWhat is due
Friday 15 JanuaryFourth quarter 2026 estimated tax payment for individuals
Monday 1 FebruaryForms W-2 to employees and the SSA, and Forms 1099-NEC to recipients and the IRS (31 January is a Sunday)
Monday 15 MarchPartnership returns (Form 1065) and S corporation returns (Form 1120-S), or extensions
Wednesday 31 MarchMost other information returns filed electronically with the IRS
Thursday 15 AprilIndividual returns (Form 1040), C corporation returns (Form 1120), trust and estate returns (Form 1041), or extensions; first quarter 2027 estimated tax; FBAR (FinCEN Form 114), with an automatic extension to 15 October
Monday 17 MayExempt organisation returns (Form 990 series), or extensions (15 May is a Saturday)
Tuesday 15 JuneSecond quarter estimated tax; Form 1040 for United States citizens and residents living abroad under the automatic two month extension
Monday 2 AugustForm 5500 for calendar year employee benefit plans, or Form 5558 extension (31 July is a Saturday)
Wednesday 15 SeptemberExtended Forms 1065 and 1120-S; third quarter estimated tax
Thursday 30 SeptemberExtended Form 1041
Friday 15 OctoberExtended Forms 1040 and 1120; extended FBAR; extended Form 5500
Monday 15 NovemberExtended Form 990 series returns

Planning capacity around the dates

Most firms feel two peaks: the weeks before 15 March and 15 April, and the weeks before 15 September and 15 October. Work out the hours each peak needs early; the capacity planner does the arithmetic.

General information for accounting professionals, not legal or tax advice. Confirm requirements against current law and IRS guidance.

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