How Is My Business Taxed by the IRS?

By Bill Stilwell · Last reviewed October 17, 2026

The short answer

Your federal tax classification is how the Internal Revenue Service (IRS) treats your business for income tax: as a sole proprietorship, partnership, C corporation, or S corporation. A limited liability company (LLC) gets a default: one owner is treated as part of the owner’s own return, and two or more owners are treated as a partnership. You can change that by filing Form 8832 to be taxed as a corporation, or Form 2553 to be taxed as an S corporation if you qualify.

What this means

Your legal structure (set with your state) and your tax classification (set with the IRS) are related but different. An LLC is a state structure. The IRS doesn’t have a separate LLC tax category, so it puts every LLC into one of the other groups.

Here are the IRS defaults:

Business	Default IRS treatment	Main federal return
Sole proprietor	Part of the owner’s return	Form 1040 with Schedule C
Single-member LLC	“Disregarded,” meaning part of the owner’s return	Form 1040 with Schedule C for a person who owns it
Multi-member LLC	Partnership	Form 1065, with a Schedule K-1 to each owner
Partnership	Partnership	Form 1065
Corporation	C corporation	Form 1120

The IRS notes that a single-member LLC is still treated as a separate business for employment taxes and certain excise taxes, even though it’s disregarded for income tax.

Two forms can change the default:

Form 8832, Entity Classification Election. An LLC files it to be taxed as a corporation. The IRS says that after you change classification, you generally can’t change again for 60 months.
Form 2553, Election by a Small Business Corporation. A corporation or a qualifying LLC files it to be taxed as an S corporation. The IRS instructions say to file it no more than 2 months and 15 days after the start of the tax year the election should take effect, or anytime in the year before. S corporations can have no more than 100 shareholders, only certain kinds of owners, and one class of stock.

Made-up example: Two friends start Ridgeline Painting LLC. With no election, the IRS treats it as a partnership. It files Form 1065 each year, and each owner reports a share of the profit on their own return. After a year, their CPA suggests looking at an S corporation election, and they meet with her before the deadline.

Why it matters

It decides what you file. Each classification has its own return and due date (see 10.1.6 Federal Filings).
It affects how you pay yourself. Owners of partnerships and sole proprietorships take draws. S corporation owners who work in the business generally need to take a salary through payroll.
It affects self-employment and payroll taxes.
Elections have deadlines. Miss the S corporation window and you may wait a year or need to request relief.
Changes have side effects. The IRS warns that changing classification can trigger deemed transactions with their own tax results.

Who this applies to

Every business has a federal tax classification. Sole proprietors and single-member LLC owners should still know their default. LLCs and corporations considering an election should talk with a CPA first. Most states follow the federal classification, but some treat LLCs or S corporations differently or charge their own entity taxes. Check with your state tax department (see 10.2.1 State Income Tax).

How to do it

Confirm your legal structure with your state formation papers (see 9.1.1 Formation-State Registration).
Find your default from the table above.
Look at your EIN application. The entity type you chose should match (see 10.1.1 Employer Identification Number).
Meet with a CPA before choosing an election. Bring your expected profit, how you plan to pay yourself, and your plans for owners and growth.
If you elect, file the right form on time. Form 2553 has a tight window. Form 8832 has its own effective date rules in its instructions.
Get every required signature. Form 2553 generally needs consent from shareholders, and spouses with a community property interest may need to sign too.
Wait for the IRS letter confirming the election, and save it.
Set up what the classification needs. For example, an S corporation owner who works in the business generally needs payroll (see 23.5 Payroll Setup).
Record the classification in your Master Business Record and tell your bookkeeper.

What proof to keep

Formation documents
Your EIN confirmation letter showing the entity type
Copies of any Form 8832 or Form 2553 you filed, with proof of filing
The IRS acceptance letter
Your CPA’s written recommendation

Keep these permanently with your formation records.

Common mistakes

Thinking an LLC is its own tax type. The IRS puts it in another group.
Missing the Form 2553 window. It’s measured from the start of the tax year.
Electing S corporation status without setting up payroll.
Forgetting a signature. Missing consents can make the election invalid.
Changing back and forth. The 60-month limit can lock you in.
Assuming the state follows the federal choice. Some states don’t.

When to get help from a pro

CPA or enrolled agent: before any election. Questions to ask:

Given my expected profit, which classification makes sense for me?
If I elect S corporation status, what salary is reasonable, and what will payroll cost?
Does my state treat my classification differently?

Bill’s note

[Bill: add a short note. For example, how you decided on SiteSmarty’s tax classification and what your CPA told you to think about.]

How I did this for SiteSmarty

[Date I did this:]
[What I actually did, step by step: SiteSmarty’s structure, its default classification, and any election I made]
[What it cost and how long it took:]
[What surprised me or what I’d do differently:]
[Screenshot or photo to add, with private info blurred: the IRS acceptance letter or EIN letter showing entity type]
[Result so far:]

Questions people ask

How is a single-member LLC taxed? By default, the IRS treats it as part of the owner’s return. A person who owns it usually reports business income on Schedule C.

How is a multi-member LLC taxed? By default, as a partnership. It files Form 1065, and each owner gets a Schedule K-1.

When do I file Form 2553? No more than 2 months and 15 days after the start of the tax year you want S corporation status to begin, or anytime in the year before.

Can I change my classification later? Yes, but after a change you generally can’t change again for 60 months, and a change can have tax side effects.

Does my state follow the IRS classification? Many do, but not all. Check with your state tax department.

Audit check

Question: Does the business know its federal tax classification, and are any elections filed, accepted, and on record?
Pass looks like: Classification matches the structure and EIN. Any election filed on time with all signatures. IRS acceptance letter on file. Payroll in place if required.
Fail looks like: Owner unsure how the business is taxed. Election missed or missing signatures. S corporation with no payroll for working owners.
Evidence to collect: Formation papers, EIN letter, election forms and acceptance letters, and the CPA’s recommendation.

Where this fits

Do this first: 8.6.1 Sole Proprietorship, 8.6.2 Partnership, 8.6.3 Limited Liability Company, 8.6.4 Corporation, 10.1.1 Employer Identification Number

Do this next: 10.1.3 Tax Year

Sources

IRS, "LLC filing as a corporation or partnership" (checked October 17, 2026)
IRS, "Limited liability company: Possible repercussions" (checked October 17, 2026)
IRS, "Instructions for Form 2553" (checked October 17, 2026)
IRS, "Entities" FAQs (checked October 17, 2026)

This page explains general rules and Bill's own experience. It is not legal, tax, or insurance advice. Talk to a qualified professional about your situation.