What Are the September Tax Deadlines?

The Internal Revenue Service establishes a calendar of tax deadlines that taxpayers must follow to remain compliant with federal law. These dates are structured to ensure the consistent collection of tax revenue throughout the year. For both individuals and business entities, understanding and meeting these obligations is a fundamental aspect of financial management. Missing a deadline can result in penalties and interest charges.

While April 15 is the most recognized tax date, several other deadlines throughout the year are just as important for millions of taxpayers. September, in particular, holds dates that apply to specific groups of individuals and businesses. Navigating these requirements involves knowing which deadlines apply to your situation and preparing in advance to file returns or make payments accurately and on time.

September Deadlines for Individuals

The primary federal tax deadline for individuals in September revolves around estimated tax payments. This requirement applies to people who earn income not subject to automatic withholding, such as the self-employed, freelancers, and independent contractors. It also includes individuals who receive significant income from other sources like interest, dividends, capital gains, or alimony. The purpose of these quarterly payments is to ensure that taxes are paid on income as it is earned.

The deadline for the third quarter estimated tax payment is September 15. If this date happens to fall on a weekend or a legal holiday, the deadline automatically shifts to the next business day. This payment covers income earned from June 1 to August 31. Failing to make this payment, or underpaying the amount due, can lead to penalties.

These payments are submitted using Form 1040-ES, Estimated Tax for Individuals. It is important for taxpayers in this category to carefully track their income and expenses throughout the year to ensure their estimated payments are sufficient to cover their eventual tax liability. This proactive approach helps avoid a large tax bill and potential penalties when the annual income tax return is filed.

September Deadlines for Business Entities

For certain business entities, September marks the final deadline to file their annual income tax return, but only if they have previously filed for an extension. This deadline specifically impacts pass-through entities such as S corporations and partnerships. These businesses, which normally face a March 15 filing deadline, can request an automatic six-month extension by filing Form 7004. This extension pushes their final due date to September 15.

S corporations file their annual return on Form 1120-S, and partnerships use Form 1065. The extension grants more time to file the return, not more time to pay any taxes owed. The tax liability for the business was still estimated and due by the original March deadline. The September deadline is strictly for submitting the completed and accurate informational return.

This information is then passed through to the owners or partners via a Schedule K-1. Additionally, trusts and estates operating on a calendar year that requested an extension for their Form 1041 return face a final deadline of September 30.

Calculating Your Estimated Tax Payment

To accurately calculate your estimated tax payment, you must first project your income for the entire year. This involves estimating your expected adjusted gross income (AGI), which includes all sources of taxable income minus specific deductions. You will also need to forecast your potential tax deductions and any tax credits you anticipate claiming.

The primary tool for this calculation is the worksheet included in Form 1040-ES. This worksheet guides you through a step-by-step process of calculating your total expected tax liability for the year. After determining the total tax, you divide it by four to arrive at your quarterly payment amount. If you have any federal income tax being withheld from other sources, you can subtract that amount from your expected liability before calculating the quarterly payments.

For individuals whose income fluctuates significantly, the annualized income installment method may be a more suitable approach. This method allows you to adjust your payment amount for each quarter based on the income actually earned during that period, rather than paying four equal installments. The specifics for this calculation are detailed in IRS Publication 505, Tax Withholding and Estimated Tax.

How to Make a Payment or File a Return

Once you have calculated the amount of your individual estimated tax payment, the IRS offers several methods for submission. The most efficient options are electronic:

• IRS Direct Pay allows you to make a payment directly from your checking or savings account at no cost.
• The Electronic Federal Tax Payment System (EFTPS) is a free government service that allows for scheduling payments in advance.
• You can also pay via debit card, credit card, or digital wallet, though third-party processing fees will apply.

For those who prefer a more traditional method, payments can be mailed. You must include a payment voucher from Form 1040-ES. You should send a check or money order made payable to the “U.S. Treasury” and write your Social Security number and the tax year on the payment.

For businesses filing their extended S corporation (Form 1120-S) or partnership (Form 1065) returns, electronic filing is the standard and preferred method. Most businesses use professional tax software or the services of a tax preparer to complete and submit these returns. E-filing is more secure, reduces the likelihood of errors, and provides an immediate confirmation that the IRS has received the return.