US Tax Filing Deadlines Every Business Should Know

Staying current with your business tax filing obligations is essential to avoid IRS penalties, interest charges, and unnecessary stress. Whether you operate as a sole proprietor, LLC, S-Corp, or C-Corp, understanding and adhering to the IRS tax calendar is crucial for maintaining compliance and financial stability. 

In this guide to the tax filing deadlines, we will cover the most critical tax deadlines for businesses in the states, who they apply to, and what forms must be filed. One bonus tip – KMK will help you stay organized and on top of these tax filing deadlines with its specialized tax team all year round. 

Key Tax Deadlines for Business: 

Here is a month-by-month detailed breakdown of the necessary tax deadlines that every business, tax professional, and CPA firm should know: 

January 31:  

• Form W-2 – must be filed with the Social Security Administration (SSA) and distributed to the employees. 

• Forms 1099-INT and 1099-DIV must be issued to all assesses and the IRS to ensure accurate income reporting. 

• Form 1099-NEC must be sent to all contractors with non-employee compensation exceeding $900 and must also be filed with the IRS. 

• Form 940 – Federal Tax Unemployment Tax Act due for the previous year. 

• Form 945 – Annual return of withheld Federal Income Tax due 

March 01: 

• Delaware Annual Franchise Tax 

March 15: 

• Form 1120-S – IRS Income Tax Return for S-Corporations 

• Form 1065 – IRS Income Tax Return for Partnerships 

• Form 7004 – IRS Extension Filing Request form 

• Schedule K-1 – Profit sharing Statement for shareholders and partners 

April 15: 

• Form 1120 – IRS Income Tax Return for C-Corporations 

• Form 1040 with Schedule C– IRS Income Tax Return for Individuals 

• Form 4868 / Form 7004 – IRS Extension Filing Request form 

• Form 1040-ES – Form to pay Estimated Tax payments for Q1 

June 17: 

• Form 1040-ES – Form to pay Estimate Tax payments for Q2 

September 15: 

• Form 1120-S – IRS Income Tax Return for S-Corporations with Extensions 

• Form 1065 – IRS Income Tax Return for Partnerships with Extensions 

• Form 1040-ES – Form to pay Estimate Tax payments for Q3 

October 15: 

• Form 1120 – IRS Income Tax Return for C-Corporations with Extensions 

• Form 1040 with Schedule C– IRS Income Tax Return for Individuals with Extensions 

Why Is It Crucial to Understand Tax Deadlines? 

Failing to meet the IRS tax filing deadlines can result in a significant number of consequences for the businesses, including: 

1. Late filing penalties: The IRS may assess significant penalties for failing to submit returns on time, which can increase monthly based on the unpaid tax amount and the duration of the delay. 
2. Interest on outstanding taxes: Unpaid tax balances begin accruing interest from the original due date until the balance is paid in full, resulting in increased financial liability. 
3. Loss of tax deductions and credits: Missing deadlines can lead to the disqualification or loss of valuable tax deductions and credits, which could have otherwise reduced the business’s tax liability. 
4. Operational Disruptions: Delays in compliance may trigger audits, enforcement actions, or strained relationships with vendors and financial institutions. This can disrupt the day-to-day business operations. 

Given these potential implications, business owners and financial managers must thoroughly understand US tax filing requirements. Proactively tracking and documenting all relevant tax deadlines – Federal, State, and Local – is a best practice that can help ensure timely compliance. Implementing reliable systems or using tax professionals to monitor important dates and filing obligations is critical to maintaining financial health and regulatory good standing. 

Read Also: Why Early E-Filing is a Game-Changer: Avoid the Last-Minute Tax Rush 

Standard Forms and Who Should File Them 

Form	Purpose	Who Files the form
Form 1120	Tax return for C Corporations	C Corporations
Form 1120-S	Tax return for S Corporations	S Corporations
Form 1065	Tax Return for Partnerships	Partnerships
Schedule C	Income Report for Sole Proprietors	Self-Employed / Single Member LLC
Form 1099-NEC	Report Contractor Payments	Businesses paying Freelancers
Form 940	Annual FUTA Tax Report	Employer
Form 941	Quarterly Payroll Tax Report	Employer
Form 7004	Extension for Business Returns	All Businesses
Form 4868	Extension for Individual Returns	Sole Proprietors, Individuals

 

Implications of missing a Deadline: 

Missing tax deadlines can result in: 

• Late filing penalties: Usually, 5% of the unpaid taxes for each month the tax remains unpaid. 

• Late payment penalties: Usually, the IRS charges 0.5% of the unpaid taxes for each month until the tax is paid in full. 

• Interest Charges: Interest is charged by the IRS, compounded daily on outstanding tax balances. 

• Loss of good standing: The status of good standing is lost by businesses with state and federal agencies. 

It is always considered a best practice to file the taxes on time. You can always apply for an IRS Payment Plan to avoid harsher penalties and fees, including interest. 

Tips to Stay Compliant with Tax Deadlines: 

1. Create a Tax Calendar with recurring reminders. 
2. Use Accounting software like QuickBooks to track income, expenses, and filing requirements. 
3. Work with CPAs or tax advisors who can advise on the compliances required and help you stay on top of your taxes. 
4. Consider outsourcing payroll to portals such as Gusto, ADP, Paychex, etc., to avoid missed deadlines for Form 941 and W-2s. 
5. Stay updated with the latest guidelines and amendments from the IRS and state-specific laws. IRS & State Specific Laws might differ for certain states. 

How KMK Can Help 

At KMK, we specialize in helping businesses navigate the complexities of tax compliance with accuracy and efficiency. From filing W-2s, 1099s, and other year-end informational returns to managing monthly, quarterly, and annual tax obligations, our team of experienced tax professionals is equipped to handle it all. 

We work closely with clients to ensure every filing is accurate and submitted on time – minimizing the risk of penalties and freeing you to focus on growing your business. Whether you are a startup, a small business, or an established corporation, our tailored approach ensures that your unique needs are met with precision and care. 

Our proactive tax planning and compliance services include: 

• Preparation and electronic filing of W-2s, 1099s, and other IRS forms 

• Ongoing monitoring of tax deadlines to ensure timely compliance 

• Calculation and submission of estimated tax payments 

• Guidance on maximizing eligible deductions and credits 

Let KMK be your trusted partner in tax compliance. Contact us at info@kmkventures.com to schedule a free consultation and learn how we can help simplify your tax responsibilities. 

Final Thoughts 

Navigating business taxes in the US doesn’t have to be overwhelming. The key to staying compliant and avoiding unnecessary financial setbacks is to stay informed, organized, and proactive. 

By keeping track of key IRS filing deadlines, ensuring the correct forms are submitted, and partnering with trusted tax professionals like KMK, you can significantly reduce your tax risk and maintain the financial health of your business. With the proper support, tax season becomes just another part of a well-managed business—not a source of stress. 

Take control of your tax responsibilities today—with KMK by your side, you’re never alone.