C corp double taxation: how it works

Double taxation is the main reason small businesses avoid the C corporation. It is real, but it only bites on profit actually paid out as dividends, and for some businesses the 21% rate on retained profit is an advantage. This guide explains how it works, with numbers.

By Mirza Fahad Baig, Chartered Accountant. Reviewed by Awais Jameel, Chartered Accountant. Checked against official sources on . 3 minute read.

Short answer

C corp double taxation means profit is taxed twice: first by the corporation at 21%, then again when paid to shareholders as dividends, at up to 20% plus the 3.8% net investment income tax. On $100,000 of profit fully paid out to a top-bracket owner, the combined tax is about $39,800. Salaries, retained earnings and an S election are the usual ways to reduce it.

At a glance

First layer
21% corporate tax on profit
Second layer
Up to 20% on qualified dividends
Plus
3.8% net investment income tax for higher earners
Combined, top rate
About 39.8% on profit paid out
Retained profit
Taxed once at 21% until paid out
Foreign shareholders
30% withholding on dividends, or a treaty rate
C corp double taxation: how it worksFirst layer: 21% corporate tax on profit; Second layer: Up to 20% on qualified dividends; Plus: 3.8% net investment income tax for higher earners; Combined, top rate: About 39.8% on profit paid out; Retained profit: Taxed once at 21% until paid out; Foreign shareholders: 30% withholding on dividends, or a treaty rate.KEY FACTS AT A GLANCEC corp double taxation: how it worksFirst layer21% corporate tax onprofitSecond layerUp to 20% on qualifieddividendsPlus3.8% net investmentincome tax for higherearnersCombined, top rateAbout 39.8% on profitpaid outRetained profitTaxed once at 21% untilpaid outForeign shareholders30% withholding ondividends, or a treatyrateChecked against official sourcesTax BakersC corp double taxation: how it worksFirst layer: 21% corporate tax on profit; Second layer: Up to 20% on qualified dividends; Plus: 3.8% net investment income tax for higher earners; Combined, top rate: About 39.8% on profit paid out; Retained profit: Taxed once at 21% until paid out; Foreign shareholders: 30% withholding on dividends, or a treaty rate.KEY FACTS AT A GLANCEC corp double taxation: how itworksFirst layer21% corporate tax on profitSecond layerUp to 20% on qualified dividendsPlus3.8% net investment income tax for higherearnersCombined, top rateAbout 39.8% on profit paid outRetained profitTaxed once at 21% until paid outForeign shareholders30% withholding on dividends, or a treatyrateChecked against official sourcesTax Bakers
Key facts at a glance, as set out in this guide.

How does it work?

A C corporation is a separate taxpayer. It pays federal income tax at a flat 21% on its taxable profit. When it pays out what is left as dividends, shareholders pay tax again on what they receive. Qualified dividends are taxed at 0%, 15% or 20%, depending on the shareholder's income, and higher earners pay the 3.8% net investment income tax on top. See Form 1120.

What does it cost in numbers?

$100,000 of profit, all paid outTop-bracket ownerOwner at the 15% dividend rate
Corporate tax at 21%$21,000$21,000
Dividend paid$79,000$79,000
Dividend tax$18,802 at 23.8%$11,850 at 15%
Total tax$39,802$32,850
Combined rateAbout 39.8%About 32.9%

State corporate and personal taxes come on top in most states.

How do owners reduce it?

  1. Pay reasonable salaries

    Salaries are deductible to the corporation, so they are taxed once, though payroll taxes apply.

  2. Retain profit for growth

    Profit kept in the business is taxed only at 21% until paid out.

  3. Use deductible benefits

    Retirement contributions and some fringe benefits for employees, including owner-employees.

  4. Plan for a sale

    Qualified small business stock can make some or all of the gain on selling shares tax-free.

  5. Consider an S election

    If eligible, profit passes through and is taxed once.

How does an S corporation or LLC compare?

With an S corporation or an LLC taxed by default, the same $100,000 of profit is taxed once, on the owner's personal return, at their marginal rate, and the qualified business income deduction can reduce it further. Self-employment tax or payroll tax also applies to some or all of it. For an owner who takes all profit out each year, single taxation is usually cheaper. See when an S corp election saves tax.

Do state taxes add to it?

Yes. Most states tax corporate profit too, and also tax dividends as personal income, so the combined rate can be noticeably higher than the federal figures above. A few states have no corporate income tax or no personal income tax.

Are there limits on keeping profit inside?

Yes. A corporation that accumulates profit beyond the reasonable needs of the business, generally above $250,000, to avoid dividend tax can face a 20% accumulated earnings tax. Retaining for real expansion plans is fine; document them. Salaries must also be reasonable for the work done.

When is a C corporation still the right choice?

When profits will be reinvested for years, when venture investors are involved, when the founders want qualified small business stock treatment, or when the owners are not eligible for an S corporation, such as non-resident aliens. See LLC vs S corp vs C corp and Delaware C corp for startups.

How does it work for foreign shareholders?

Dividends paid to a foreign shareholder are generally subject to 30% US withholding, or a lower treaty rate, instead of the US dividend tax rates. The shareholder's home country may tax the dividend too, with credit for the US tax. See the 30% withholding.

Weighing a C corporation?

We model your profits under a C corporation, an S corporation and an LLC, including salary and dividends, so you can choose on actual numbers.

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Questions people ask

What is C corp double taxation?

Profit taxed once at 21% by the corporation, and again when paid to shareholders as dividends.

What is the combined tax rate on C corp dividends?

About 39.8% for a top-bracket owner: 21% at the corporation, then 23.8% on the dividend.

How can I avoid double taxation in a C corporation?

Pay reasonable salaries, retain profit for growth, use deductible benefits, or elect S status if eligible.

Does double taxation apply to profit kept in the company?

Not until it is paid out. Retained profit is taxed only at 21%, within the accumulated earnings rules.

Sources

Every fee, date and rule on this page was taken from these official and primary sources.

  1. IRS: Instructions for Form 1120 (2025)
  2. IRS: Topic no. 404, Dividends
  3. IRS: Net investment income tax
  4. Internal Revenue Code sections 531 to 537: accumulated earnings tax

Rules and fees change. If you are reading this long after October 1, 2026, confirm the figures with the source before you rely on them.

Starting a US companyLLC vs S corp vs C corp: which one fits your businessFederal tax formsForm 1120: the C corporation returnBusiness tax by entity typeS corp election: when it saves tax and when it doesn't

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This guide is general information. It is not tax or legal advice for your situation.