Methodology
How the numbers are produced
Every figure on this site comes from a primary source and is checked by 387 automated assertions before it ships. Here is exactly what that means, and what it does not.
Sources: agencies, not other websites
Tax figures come from the IRS, the Internal Revenue Code, and the revenue department or Secretary of State of the relevant jurisdiction. They are not copied from other calculators, comparison sites or fee tables.
That rule exists because of a specific incident rather than as a principle. While compiling the LLC fee dataset, a widely-cited source listed Delaware’s annual LLC tax as $400. It is $300. Delaware is the most-searched state in that niche, so publishing the aggregator’s number would have discredited the entire tool. Since then, any figure that disagrees between sources is treated as unverified until it is resolved against the agency itself.
The same audit later found that seventeen states levy a tax on the LLC entity regardless of profit, and that six of them were missing from the dataset entirely — Kentucky’s limited liability entity tax among them. Most published fee tables still omit all of it. That work is public: see the open datasets, which carry their own provenance and caveats.
Verification: 387 assertions, run before every deploy
The tax logic is not trusted because it looks right. It is checked against hand-computed cases by four test suites that must pass before anything ships.
| Suite | Checks | What it asserts |
|---|---|---|
| Federal tax maths, 2026 | 112 | SE tax, brackets, QBI, retirement caps and the deduction interactions, against hand-computed cases |
| Federal tax maths, 2025 | 76 | the same, against the closed year’s published figures |
| LLC fees and state pages | 180 | every fee, entity-level tax and per-state page against the compiled dataset |
| State income tax | 19 | bracket and flat-rate handling across the state set |
| Total | 387 |
A separate audit crawls the published site on every deploy and fails the build if a page has a broken internal link, a missing canonical, a duplicate title, or has become uncrawlable.
Tax years are pinned, not migrated
A page that says it computes tax year 2025 will still compute tax year 2025 next year. The calculation logic lives in one place and the per-year constants in another, so adding a new year cannot silently change an old one. Where both years are available, the page carries a year switcher and states which one it is using.
What this site does not claim
No one here is a CPA, an enrolled agent or an attorney. This is a publication, not a practice. Nothing on it is tax, legal or financial advice, and it cannot be — advice requires knowing your circumstances, and the calculators deliberately never see them.
What the tools give you is an estimate built from published rules, with the method stated and the limits named on each page. That is genuinely useful for planning, for sanity-checking a preparer, and for understanding why a number is what it is. It is not a substitute for a professional on anything consequential, and where a question is genuinely unsettled — as the self-employment tax treatment of a partner’s distributive share currently is — the guides say so rather than picking the confident-sounding answer.
Every page also states its country. Everything here is United States federal tax unless it says otherwise. US rules applied to a non-US return produce a figure that means nothing, which is worse than no figure at all.
Currency and corrections
Tax rules change, and state fees change more often than anything else here. Each page carries the date it was last reviewed, and each dataset carries the date it was compiled plus a dated changelog. Where a figure is known to be volatile, the page says to confirm it with the agency — that is not boilerplate hedging, it is the honest position.
Corrections are genuinely welcome and are acted on. If a number here is wrong, telling us is the fastest way to get it fixed, and errors are corrected rather than quietly overwritten. Email hello@thenumberdesk.com or use the contact page. Point at the page and the figure, and if you have the agency source to hand, include it — that turns a fix into minutes.
Who publishes this
The Number Desk is an independent publisher. It is not owned by, funded by or affiliated with any accounting firm, formation service, payroll provider or financial institution, and it does not sell leads. Nothing on the site is placed or influenced by a third party.
It is paid for by advertising. There is no paid tier, no subscription, no gated content and no email wall. If a page ever recommends a paid product, the page will say so plainly. See About for more, and the privacy policy for what happens to your data — which, for the calculators, is nothing: they run entirely in your browser.