INSIGHTS
It’s time! What to prepare for tax year 2025 filing
by Larson Gross
ARTICLE | January 14, 2026
Yes, it’s time to get started preparing for your 2025 tax return. Upping your organizational game and understanding what you need and when will eliminate the last-minute scrambles to meet deadlines, and it might just improve your financial results, too.
Whether you’re an individual taxpayer or business owner, starting early can reduce delays, minimize errors, and help your tax pros do their best work on your behalf. Our team has put together a practical guide to get you started on the right foot this tax season, including key deadlines, commonly required documents, and planning considerations.
Important deadlines
The 2025 tax year covers income earned from January 1 through December 31, 2025, with returns generally filed in 2026. Important deadlines to keep in mind include:
February 2, 2026:
- Employers must issue Forms W-2 for regular employees on payroll
- Businesses must issue Forms 1099-NEC and 1099-MISC for pay issued to non-employees, such as contractors, freelancers, gig workers, etc.
Normally, the deadline is January 31, but since that date falls on Saturday this year, the deadline is Monday, February 2.
March 16, 2026:
- Calendar year S-Corporation and Partnership returns due (Forms 1120-S and 1065)
These returns are normally due March 15, but it’s a Sunday this year. You’ve got an extra day, if you need it. (We hope you’re not pushing it that close to the wire!)
April 15, 2026:
- Individual income tax returns (Form 1040) due
- First-quarter estimated tax payment for 2026 due
- Trust returns (Form 1041) due – extension due date is September 30, 2026
May 15, 2026:
- Nonprofit/Tax-exempt entities (Form 990) due – extension due date is November 16, 2026
September 15, 2026
- Deadline for individual return extensions
- Third-quarter 2026 estimated tax payments are due for individuals and most calendar-year C corporations.
- Extended S corporation and partnership returns (Forms 1120-S and 1065) for calendar-year entities on extension
- The September 15 deadline also applies to many multi-member LLCs taxed as partnerships (Form 1065) are on extension
- Some corporations with short tax years ending June 30, 2026 may have a September 15, 2026 filing deadline under IRS tax calendar rules
October 15, 2026
- Extended deadline for individual returns (if an extension is filed)
A note about filing extensions: The important thing to remember is that while extensions provide extra time to submit your return, they do not extend the time to pay taxes owed—you’ll still need to send a check to Uncle Sam by the deadline date, if you owe.
Personal tax preparation checklistIf you’re preparing an individual tax return, gather the following documents as early as possible: Income Documents
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Other Important Items
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Business Tax Preparation ChecklistFor business owners, early organization is especially important. Key items include: Financial Records
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Compliance and Reporting
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Well-maintained bookkeeping throughout the year can significantly reduce preparation time and help avoid filing delays. Our firm can help with that!
Estimated taxes and withholding review
If you’re self-employed, receive investment income, or have multiple income sources, reviewing your estimated tax payments is essential. Underpayment can result in IRS penalties, even if you ultimately owe only a small balance at filing time. Individuals may also benefit from reviewing their withholding elections to ensure they align with current income levels and personal circumstances to avoid over- or underpayment.
Common Filing Mistakes to Avoid
Each tax season, taxpayers encounter preventable issues that slow processing or trigger notices. Some of the most common include:
- Missing or incorrect Social Security numbers
- Reporting income that doesn’t match IRS records
- Forgetting estimated tax payments already made
- Claiming credits without proper documentation
- Filing before receiving all tax forms
Taking time to confirm completeness and accuracy before filing can prevent snags in processing or IRS audits. Working with a tax professional will give you an advantage.
Starting your tax preparation early is always a good idea. An early start gives you more time to resolve issues like missing documents, and less pressured work reduces the risk of errors and gives more time for planning. You’ll be able to focus more on accuracy and strategy rather than last-minute urgency.
Getting professional help is worth it!
Remember the part about tax preparation and filing not having to be dreadful? Engaging the services of a professional tax team can make all the difference, and it will likely pay for itself in mistake and penalty avoidance, recouping your irreplaceable time, and trading anxiety for peace of mind. Whether you’re filing a complex individual return or trying to keep your business compliant, our team’s expertise will help improve the process.
Whether you work with our team or another professional, start working sooner, rather than later. The clock is ticking!
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Meaghan Greydanus, CPA, MPASS
Partner, Larson Gross
A native of Gig Harbor, Washington, Meaghan completed her Master of Professional Accounting in Taxation at the University of Washington. She’s connected with various professional organizations including the Washington Society of CPAs and the American Institute of Certified Public Accountants. Her primary areas of accounting are tax research, tax planning, partnership, corporate, individual, and estate taxation.
