Every rate carries its receipt.
Most tax calculators show you a number and ask for your trust. This one shows you the number and the rule behind it.
Why this site exists
Self-employed tax in the United States is not hard to compute — it is hard to check. The formulas are public. The rates are published. What is missing from most online calculators is any way to confirm that the figure you were given is the figure the law actually produces.
So every calculator here does two things at once: it computes, and it shows the source of every constant it used — the IRS revenue procedure, notice, or SSA release, with the date it was verified. If a number cannot be traced to an official source, it is not published here.
How the figures are verified
- Federal constants come from the IRS and the Social Security Administration. Each one is dated on the page that uses it.
- State figures come from the state's own revenue department, never from a summary or a blog. A state whose rates the authority has not published yet does not appear in the calculator at all.
- Provisional figures are labelled as such. When a tax authority announces amounts but has not published final schedules, the page says so rather than presenting an estimate as settled.
- Every constant carries a test. If a rate changes and the change is not made deliberately, an automated check fails and reports the correct value. That is how a wrong mileage rate or a stale threshold gets caught instead of shipping.
What this site is not
It is not tax advice, and it is not a replacement for a CPA. The calculators model common situations; your situation may have credits, carryovers or entity elections that a general tool cannot know about. See the Terms of Use for the full scope.
The calculators
Each one lives on its own page with its own explanation of the formula behind it:
- Self-Employment Tax Calculator — SECA tax, the deductible half, and the quarterly set-aside.
- Quarterly Tax Calculator — what to send with each 1040-ES, with federal and state tax and the safe harbor rule.
More are added as their figures are verified against source. A calculator is not published until its constants are.
Contact
Corrections are welcome and taken seriously. If you find a figure that disagrees with an official source, please send it: [email protected]
Include the page and the source you are comparing against. Reports that cite an official document get priority.