Tax OrganizerJan152027
Estimated taxes
Step 1
Final 2026 personal estimate
Fourth quarter 2026 estimated tax payment for individuals and many pass-through owners.
Federal income tax calendar
Tax Deadlines
A client-friendly view of the major federal income tax deadlines, how the dates relate to each other, and how CPA Web Books is addressing review bottlenecks now with better technology integrated into our team workflow before next tax season.
Calendar-year federal dates
The dates below focus on calendar-year taxpayers and the 2026 tax year filed in 2027. Fiscal-year taxpayers, disaster relief, legal holidays, and special situations can change the deadlines. An extension gives more time to file, but tax payments are generally still due by the original deadline.
How the season fits together
Think of the deadlines as a chain: estimated payments happen during the year, pass-through business returns come first, then personal returns, then extension season.
Mar152027
Entity returns
Step 2
Pass-through returns
Calendar-year partnerships and S corporations file or extend. K-1 timing affects many personal returns.
Apr152027
Personal returns
Step 3
Main individual deadline
Individuals, many C corporations, and calendar-year estates and trusts file or extend. Payment is still due.
May172027
Nonprofits
Step 4
Calendar-year 990 deadline
May 15 falls on a Saturday in 2027, so calendar-year exempt organization returns generally move to Monday.
Sep152027
Extension season
Step 5
Pass-through extended due date
Extended calendar-year partnerships and S corporations are generally due.
Sep302027
Extension season
Step 6
Trust and estate extended due date
Calendar-year Form 1041 returns generally receive a 5.5-month filing extension.
Oct152027
Extension season
Step 7
Individual and C corporation extensions
Extended individual Form 1040 and many calendar-year C corporation returns are generally due.
Nov152027
Extension season
Step 8
990 extended due date
Extended calendar-year Forms 990, 990-EZ, 990-PF, and 990-N are generally due.
Return deadlines by type
These are the common federal deadlines clients ask about most often. The dates assume a calendar-year taxpayer.
Return typeFormOriginal due dateExtended due dateWhy it matters
Return type
Individuals
Form
Form 1040
Original due date
Apr 15, 2027
Extended due date
Oct 15, 2027
Extension gives more time to file, not more time to pay.
Return type
Partnerships
Form
Form 1065
Original due date
Mar 15, 2027
Extended due date
Sep 15, 2027
K-1s from this return often drive the owners' personal returns.
Return type
S corporations
Form
Form 1120-S
Original due date
Mar 15, 2027
Extended due date
Sep 15, 2027
Shareholder K-1s should be ready before personal returns can be finished.
Return type
C corporations
Form
Form 1120
Original due date
Apr 15, 2027
Extended due date
Oct 15, 2027
Calendar-year C corporations generally pay their own income tax directly.
Return type
Estates and trusts
Form
Form 1041
Original due date
Apr 15, 2027
Extended due date
Sep 30, 2027
Calendar-year Form 1041 returns generally have a 5.5-month extension.
Return type
Nonprofits
Form
Forms 990, 990-EZ, 990-PF, 990-N
Original due date
May 17, 2027
Extended due date
Nov 15, 2027
Calendar-year 990s normally fall on May 15; 2027 moves because May 15 is Saturday.
Estimated tax rhythm
Estimated taxes are different from return deadlines. They are payment deadlines during the year, often for individuals, owners of pass-through businesses, and C corporations.
Form 1040-ES
Personal estimated taxes
Individuals, sole proprietors, partners, and S corporation shareholders often pay tax personally on business profits through these dates.
Q1
Apr 15, 2026
Jan 1-Mar 31 income
Q2
Jun 15, 2026
Apr 1-May 31 income
Q3
Sep 15, 2026
Jun 1-Aug 31 income
Q4
Jan 15, 2027
Sep 1-Dec 31 income
Calendar-year corporation
C corporation estimates
C corporations may have their own estimated income tax payment schedule. This is different from S corporation or partnership owner estimates.
1st paymentApr 15, 2026
2nd paymentJun 15, 2026
3rd paymentSep 15, 2026
4th paymentDec 15, 2026
CPA Web Books delivery timeline
We are building next season around clearer client deadlines, cleaner organizer flow, stronger review tracking, better staff routing, and fewer last-minute surprises.
January
Organizer opens
Clients begin using the Tax Organizer as the single place for documents, questions, missing items, and signatures so the return starts cleanly.
Early season
Business info first
Partnerships and S corporations need early attention because K-1s often control the owners' personal returns and April 15 readiness.
Target to be finalized
Complete personal info
We will set clearer client information deadlines so complete returns can move through preparation and review without last-minute bottlenecks.
Tax season standard
April 15 delivery goal
Our goal is to get every return out the door by April 15 when clients meet the information deadlines and no unusual issues delay the work.
What we are fixing before next season
The goal is not just a better website. We are addressing the tax return review process and the operational bottlenecks that make tax season harder than it needs to be.
Review process rebuilt
Tax return review is being turned into a clearer tracked workflow, so returns do not sit invisibly between preparation, review, questions, and final delivery.
Bottlenecks made visible
Missing items, unanswered questions, owner K-1s, review notes, and signature steps are being organized so the team can see what is blocking a return earlier.
Technology integrated with the team
The new tools are being built around how CL, bookkeeping, preparers, reviewers, and Kevin actually work together, so the system supports the team instead of sitting off to the side.
Where we are headed
Our goal is to make tax delivery feel calmer, clearer, and more predictable. The review process, bottleneck tracking, organizer flow, and staff handoffs are being addressed now and are targeted to be fully in place before year-end. With better technology integrated into the way our team works every day, we intend to set client information deadlines that support getting returns out by April 15 whenever complete information arrives on time.
Ready to send information?
Use the Tax Organizer for documents, missing items, organizer questions, and notes tied to an active return.
Need payment or government links?
We keep IRS, state, city, payroll, bookkeeping, and firm portal links on the Tool Logins page so clients have one place to look.