About this calculator

Why this exists

Most paycheck calculators are black boxes that quietly go stale when tax rates change. This project takes the opposite approach: the calculation logic is open and deterministic, and every tax figure is tied to an official primary source with the date it was verified.

Who maintains this

This calculator is built and maintained by White Rabbit, an independent maintainer and software engineer. To be clear and honest about it: I am not a CPA, tax attorney, or enrolled agent, and nothing here is professional tax advice.

The reason you can rely on the numbers isn’t a professional credential — it’s the process. Every figure is pulled from an official primary source (the IRS, the Social Security Administration, or a state Department of Revenue), carries the date it was last verified, runs through automated sanity checks and engine tests, and is reviewed by a person before it is published. The full method is laid out on the methodologypage, and every figure’s source is listed on the sources page. If you ever find a number that looks wrong, please tell me — corrections are checked against the primary source.

How we keep numbers accurate

Tax data is stored separately from the calculation code. Each rate or threshold carries its tax year, the date it was last verified, and a link to the official source — the IRS, the Social Security Administration, or a state Department of Revenue. Before any number reaches you it passes three gates:

• Automated checks — rates within plausible ranges, brackets in order, FICA caps sane.
• Engine tests — known cases (e.g. a single filer at $100k) must still produce the expected breakdown.
• Human approval — a person confirms each change against the primary source before it is published.

Updates are prepared automatically but never published automatically. A human is always in the loop, especially because tax content is high-stakes.

Open methodology

The exact formula and the rates in use are documented on the methodologypage, and every figure’s provenance is listed on the sources page.

Not tax advice

This calculator provides estimates for general information only and is not a substitute for professional tax advice. Questions or a correction? See contact.