A calculator that is willing to say no
Most S-corp content on the internet is written by someone who sells S-corp services. That is not a conspiracy, it is just incentives - and it means the "is this worth it" question rarely gets an honest answer.
What this site does
Three calculators for US self-employed people: what you owe, whether an S-corp election actually saves money once its costs are subtracted, and what to pay each quarter. The middle one is the reason the site exists.
Where the numbers come from
Every parameter lives in a single file - the 15.3% SECA rate, the 92.35% net earnings factor, the Social Security wage base, the federal brackets, the standard deduction, the QBI rate, the additional Medicare thresholds, the quarterly due dates, and a per-state table of S-corp annual costs. Each file is stamped with the tax year it belongs to, and that year is printed on every result.
Primary sources for the federal figures
- Tax brackets and standard deduction, tax year 2026 - IRS Rev. Proc. 2025-32 (Tables 1 and 3, and section 4.14).
- OASDI wage base for 2026: $184,500 - Social Security Administration, Cost-of-Living Increase and Other Determinations for 2026, published in the Federal Register on 3 November 2025.
- Self-employment tax 15.3% on 92.35% of net earnings; additional Medicare 0.9% over $200,000 / $250,000 - statutory rates that are not inflation-indexed.
- QBI deduction of 20% - statutory.
State-level figures carry a verification flag. Anything not yet checked against the state's own publication is marked, on the page, rather than quietly presented as fact.
What the model simplifies - and why
- State income tax is one approximate rate per state. Real state tax has brackets, credits and local add-ons. This ranks decisions; it does not file returns.
- QBI is modelled as a flat 20% of qualified business income. The high-income limitations and the specified-service-trade rules are not modelled.
- Reasonable salary defaults to 40% of profit and is adjustable. That default is a convenience, not a legal standard.
- Not modelled at all: retirement plan contributions, the self-employed health insurance deduction, state estimated-tax systems, and credits of any kind.
Every result page prints the assumptions that apply to it. If a number here disagrees with your accountant, your accountant is right.
What this site refuses to do
- It does not claim an S-corp will save you money when the arithmetic says otherwise. Below the break-even point it says so.
- It does not require an email to show a result.
- It does not give tax advice, and it says that on every page rather than in small print nobody reads.
How it is built
Static HTML, one stylesheet, plain JavaScript, no accounts, no server-side computation. Your inputs stay in the page URL so a scenario can be bookmarked or sent to an accountant.
Corrections
If a rate is wrong or out of date, the fix is a line in the data file. Corrections are the most useful thing you can send.