How this tax comparison calculator helps
Choosing how a business is taxed can change both the total tax bill and the amount of cash the owner actually keeps. This calculator compares three common U.S. tax treatments using the same annual business numbers: an LLC or other pass-through setup, an S-Corp election, and a C-Corp. The goal is not to recreate a full tax return. Instead, it gives you a consistent side-by-side estimate so you can see how different tax structures respond to the same revenue, expenses, salary, and distribution assumptions.
That side-by-side view matters because the same business profit can be taxed in very different ways. In a pass-through structure, profit generally flows to the owner and may be exposed to income tax plus self-employment tax. In an S-Corp, part of the owner’s compensation is treated as salary and part may be treated as distributions, which changes payroll tax exposure. In a C-Corp, the corporation pays tax first, and then the owner may pay dividend tax if profits are distributed. Looking at those systems together makes it easier to understand the tradeoffs instead of relying on broad rules of thumb.
This page is best used for planning, rough scenario testing, and better conversations with a CPA or tax attorney. It uses flat rates and simplified assumptions, so it should not be treated as filing guidance. Real outcomes can differ because actual tax law includes progressive brackets, wage bases, deductions, credits, state-specific rules, and entity-level fees that are not fully modeled here. Even so, a simplified comparison is often valuable because it shows which assumptions drive the biggest differences.
Inputs, formulas, and result interpretation
Start with your annual business numbers. Enter gross revenue first, then the major costs that reduce profit: cost of goods sold, operating expenses, depreciation or amortization, interest, and any other deductions you want included. The calculator combines those figures to estimate business income. That business income figure is the common starting point for all three entity comparisons, which helps keep the results easy to interpret.
Next, enter the tax rates you want to test. The federal tax rate field is a flat modeling rate rather than a full progressive bracket calculation. The state tax rate field is also simplified and acts as a general state income or corporate tax assumption. If your goal is comparison rather than exact return preparation, a blended rate can still be very useful. Many users run a low, medium, and high rate scenario to see whether the ranking of entity choices changes.
The entity-specific fields are where the comparison becomes more strategic. In the S-Corp section, the owner salary matters because payroll tax is applied to wages in the simplified model. A higher salary usually increases payroll tax exposure, while a lower salary may make the S-Corp look more favorable, though it may also be less realistic. In the C-Corp section, the distribution percentage matters because it determines how much after-tax corporate profit is paid out and therefore exposed to dividend tax in the current year. Retained earnings stay in the company and may support growth, but they are not current cash in the owner’s pocket.
When you review the results, do not look only at the total tax number. The owner receives figure is just as important because it shows how much modeled cash reaches the owner after the relevant taxes in each scenario. A C-Corp can sometimes look efficient when profits are retained, but that does not necessarily mean the owner has more spendable cash. The detailed breakdown below the summary table helps you see whether the difference comes from self-employment tax, payroll tax, corporate tax, dividend tax, or a change in how much profit is retained.
The calculator uses annual amounts and a simplified tax framework. The core relationships are shown below.
In plain language, the LLC model taxes the same business income at the chosen federal and state rates and adds a simplified self-employment tax. The S-Corp model applies payroll tax to salary, then applies the chosen income tax rates to total owner income and adds filing costs. The C-Corp model taxes profit at the corporate level first, then applies dividend tax only to the portion of after-tax profit that is distributed.
Worked example and limitations
Suppose a single-owner business has $150,000 of gross revenue, $30,000 of cost of goods sold, $40,000 of operating expenses, and $10,000 of combined other deductions from depreciation, interest, and miscellaneous write-offs. The business income would be $70,000. If you use a 24% federal rate and a 6% state rate, the LLC scenario applies both income taxes and self-employment tax to that $70,000 in this simplified model. That makes the LLC result easy to compare with the alternatives, even though real returns may include additional adjustments.
Now imagine the owner elects S-Corp treatment and pays a $45,000 salary. Payroll tax applies to the salary, while the remaining profit is treated as a distribution in the simplified comparison. The federal and state income tax assumptions still apply to the owner’s total income in the model, but the payroll tax base changes. That is why the salary field is the main lever in the S-Corp scenario. If you test several salary levels, you can quickly see how sensitive the result is to that assumption.
In the C-Corp version of the same example, the corporation first pays federal corporate tax at 21% plus the chosen state tax rate. Only after that does the model look at how much of the remaining profit is distributed. If all after-tax profit is paid out, the owner may owe dividend tax on the full distributed amount. If only part is distributed, current-year owner cash may be lower, but more value remains inside the company as retained earnings. That distinction is important if the business plans to reinvest rather than distribute most profits.
This calculator has clear limitations, and understanding them is part of using it well. It does not model progressive federal brackets, Social Security wage caps, additional Medicare tax, net investment income tax, the qualified business income deduction, retirement plan contributions, health insurance treatment, local taxes, franchise taxes, or special state entity fees. It also does not allocate income among multiple owners even though the owner count field is preserved. Those omissions do not make the tool unhelpful; they simply mean the output is best treated as a comparison framework rather than a filing-ready answer.
A practical way to use the calculator is to change one variable at a time. Try a higher and lower S-Corp salary. Then test a lower C-Corp distribution percentage. If the ranking of the three structures stays the same across several reasonable scenarios, that can give you more confidence about the direction of the decision. If the ranking changes easily, that is a sign the choice depends heavily on assumptions and deserves a more detailed professional review.
Introduction: Understanding the three tax structures
Why entity choice matters: the same business profit can be taxed very differently depending on whether income passes through to the owner, is split between salary and distributions, or is taxed at the corporate level first.
A useful way to think about entity choice is to separate legal structure from tax treatment. Many owners say they are choosing between an LLC, an S-Corp, and a C-Corp, but what they are often really comparing is how profit is taxed, how compensation is handled, and whether earnings are distributed or retained. This calculator focuses on those tax mechanics so you can see the broad patterns before getting into finer details with an advisor.
In a basic LLC or other pass-through setup, the business itself usually does not pay federal income tax. Instead, profit passes through to the owner or owners and is reported on their returns. In this calculator, that income is modeled with the chosen federal rate, the chosen state rate, and a simplified self-employment tax of 15.3%. That makes the LLC scenario easy to compare and also shows why some owners begin exploring S-Corp treatment as profits rise.
An S-Corp is generally a tax election rather than a completely different day-to-day business operation. Many businesses that are legally organized as LLCs elect S-Corp taxation. The key idea is that an owner who works in the business is expected to take reasonable compensation as wages. Those wages are subject to payroll taxes, while remaining profit may be distributed differently. In practice, the salary assumption is one of the most important judgment calls in the entire comparison.
A C-Corp is taxed at the corporate level. In the simplified model on this page, the corporation pays federal tax at 21% plus the chosen state tax rate on business income. After that, the remaining profit can either stay in the company or be distributed to the owner. If it is distributed, the model applies a 15% dividend tax to the distributed amount. This is the classic double-taxation concept, but the practical effect depends heavily on whether profits are paid out now or retained for growth.
None of these structures is automatically best in every situation. If administrative simplicity matters most, a pass-through setup may still be attractive even when the modeled tax cost is somewhat higher. If payroll tax savings are meaningful and the business can support a defensible salary, an S-Corp election may deserve a closer look. If the company plans to retain earnings for expansion, a C-Corp may look different than it would in a business that distributes nearly all profits each year. The value of the calculator is that it lets you test those ideas with your own numbers instead of relying on generic advice.
How to use this calculator
- Enter Gross business revenue ($) using the unit or time period shown by the field.
- Enter Cost of goods sold (COGS) ($) using the unit or time period shown by the field.
- Enter Operating expenses ($) using the unit or time period shown by the field.
- Run the calculation and compare the output with a second scenario before acting on it.
