LLC Taxes 101: How Pass-Through Taxation Works, and What an S-Corp Election Changes

A limited liability company is a state law creation — every state's business code defines what an LLC is and how it's formed. The federal tax code, by contrast, has no matching "LLC" box to check. Instead, the IRS looks at how many owners (members) the LLC has and assigns a default classification built for an entity with that many owners, unless the LLC files a separate election to be taxed differently.

The two defaults

A single-member LLC is, by default, a disregarded entity for federal tax purposes — the IRS effectively ignores the LLC as a separate taxpayer and taxes the owner directly, as if the business were a sole proprietorship, even though the state-law liability shield still fully applies. A multi-member LLC is, by default, taxed as a partnership — the entity itself doesn't pay federal income tax; instead, profits and losses pass through to the members, who report their share on their own returns.

For a single-member LLC taxed under the default disregarded-entity rule, business income and expenses are typically reported on the owner's personal return using Schedule C, with the net profit flowing into the owner's overall taxable income. For a multi-member LLC taxed as a partnership, the entity files an informational partnership return, and each member receives a Schedule K-1 reporting their specific share of the profit or loss, which they then report on their own personal return.

Pass-through means no separate entity-level tax — not no tax

"Pass-through" is sometimes misread as "the business doesn't get taxed." What it actually means is that the entity doesn't pay income tax on its own profit — the tax obligation passes through and lands on the owners instead, at their individual rates. The total tax owed doesn't disappear; it just gets assessed at a different level.

This is the part of LLC taxation that surprises a lot of first-time owners. Under the default pass-through treatment, an LLC member's full share of business profit is generally subject to self-employment tax — the mechanism that funds Social Security and Medicare for people who aren't traditional W-2 employees — not just whatever the owner formally paid themselves. There's no concept of "salary" for a default LLC member; the entire allocated profit is treated as self-employment income, in addition to regular income tax.

Why this matters for the S-corp comparison below

This self-employment tax exposure on the entire profit share, regardless of how much the owner actually draws out of the business, is the specific mechanic that an S-corp election is designed to change — which is exactly why that election gets discussed so often once an LLC becomes consistently profitable.

An LLC isn't locked into its default classification. Two different elections exist, and they do different things, which is a common source of confusion:

• Electing C-corporation tax treatment changes the entity to pay its own entity-level income tax, separate from the owners — a much less common choice for a small LLC, generally relevant only in specific reinvestment or investor-related situations.
• Electing S-corporation tax treatment keeps the pass-through structure intact — profit still flows to the owners' personal returns — but changes how that profit is categorized for self-employment tax purposes, which is the change most owners are actually asking about when they bring up "S-corp status."

An LLC that elects S-corp treatment doesn't stop being an LLC under state law; the election only changes how the IRS taxes the existing entity.

Once an LLC elects S-corp tax treatment, an owner who works in the business generally has to be paid a reasonable salary through formal payroll, with standard payroll taxes withheld — much like any other employee. Any remaining profit beyond that salary can then be distributed to the owner as a distribution, which is not subject to self-employment tax the way it would be under the default LLC treatment. That gap — salary taxed one way, remaining distributions taxed another — is the entire mechanism behind the potential savings people associate with the election.

The trade-off: more formality, not less

The election doesn't just lower a tax bill by itself — it adds real obligations. Running payroll means payroll tax filings, payroll processing (in-house or through a provider), and a defensible, IRS-reasonable salary figure that has to actually reflect the value of the work performed, not an artificially low number designed purely to minimize tax.

The election isn't a universal upgrade. The potential benefit generally only shows up once the business's profit comfortably clears what a reasonable salary for the owner's work would be — below that point, the added payroll administration and compliance overhead can cost more than the self-employment tax it saves. A handful of other factors matter too: how consistent the profit is year to year, whether the owner wants to maximize retirement-plan contributions (which are often tied to W-2 wages under an S-corp), and whether the added formality is something the owner can realistically maintain going forward.

This is precisely the kind of decision that benefits from being modeled against your actual numbers, rather than decided in the abstract — a CPA can run the comparison against your specific profit level and tell you where the break-even point actually sits.

Everything above describes federal tax treatment. States layer their own rules on top, and they don't all follow the federal default. Some states impose their own LLC-level fee or franchise tax regardless of federal classification; others largely mirror the federal pass-through treatment with no separate entity-level charge. Each state's page on this site reflects that state's specific filing and reporting requirements, and it's worth checking the state-tax picture alongside the federal one — an S-corp election, in particular, doesn't always carry the same effect at the state level that it does federally.

Both the C-corp and S-corp elections have specific filing deadlines tied to the tax year they're meant to apply to — miss the window, and the election generally doesn't take effect until the following tax year, rather than retroactively covering the year you meant it to. This is one of the more common ways owners lose out on an election they otherwise would have qualified for: not because the decision was wrong, but because it was made too late in the year to file in time.

Plan the election before the year it applies to, not during it

Because of that timing rule, the S-corp conversation is best had well before the tax year in question — not scrambled together the week before a filing deadline. A CPA who already knows the entity's numbers is far better positioned to flag the right timing than a decision made reactively at tax time.