Now booking FY 2026 · Median turnaround 72 hours
Authorized IRS e-File Provider Get a quote →
Home/Blog/How to File Form 1120 for an S Corp Tax Return
October 13, 2026 · By Guy Crouch, CPA

How to File Form 1120 for an S Corp Tax Return

Filing an S Corporation tax return requires accurate financial records and proper reporting. Although the title mentions Form 1120, S Corporations generally file Form 1120-S, which reports business income, deductions, credits, and other tax information to the IRS.

Steps to File Form 1120-S

Follow these steps to prepare your S Corporation tax return:

  1. Gather financial records: Collect income statements, expense receipts, payroll records, bank statements, and shareholder details.
  2. Calculate business income: Report revenue, deductible expenses, and other required financial information.
  3. Complete Form 1120-S: Enter the corporation's details and financial figures in the appropriate sections.
  4. Prepare Schedule K-1: Report each shareholder's share of income, deductions, and credits.
  5. Review and submit: Check the return for errors and file it by the applicable IRS deadline.
RequirementPurpose
Form 1120-SReports corporate financial information
Schedule K-1Allocates tax items to shareholders
Financial statementsSupport income and expense reporting
State tax returnsMeet applicable state filing requirements

State Filing Requirements

Federal filing is only part of the process. Businesses may also need state-specific returns. For example, a California S corporation tax return may involve additional state tax obligations. Businesses preparing an Indiana 1120s filing or a Missouri form 1120s should verify the relevant state requirements and deadlines.

Working with a professional can help businesses manage these obligations and avoid common filing mistakes.

Why Choose Strategic Accounting Solutions?

Strategic Accounting Solutions provides tax preparation and business tax advisory services to help businesses maintain accurate records, meet filing requirements, and manage their tax responsibilities. Professional assistance can simplify complex returns and support better financial decisions.

Frequently Asked Questions

1. Is Form 1120 the correct form for an S Corporation?

No. S Corporations generally file Form 1120-S, while C Corporations typically file Form 1120.

2. When is Form 1120-S due?

For calendar-year S Corporations, the usual deadline is March 15, adjusted when it falls on a weekend or holiday.

3. Do S Corporation shareholders receive separate tax forms?

Yes. Each shareholder generally receives Schedule K-1 to report their share of the corporation's tax items.

Need help filing your S Corporation tax return? Contact Strategic Accounting Solutions for professional tax preparation and advisory support to help keep your business tax filings accurate and organized.

Filing now · FY 2026

Pick your form.
We'll take it from there.

Two forms, two deadlines, one workflow. Tell us which return you're filing and we'll send the SmartVault link and document checklist within the hour.

S-Corp · Form 1120S Mar 15
—
--
Days
--
Hrs
--
Min
--
Sec
Individual · Form 1040 Apr 15
—
--
Days
--
Hrs
--
Min
--
Sec