How the tools work
How the tools on this site are built and tested.
Do the tools give the same answer every time?
Yes. Each tool's rules live in plain code, apart from the page. The same answers in give the same answer out, every time.
Every reason that states a tax rule names its source. Two kinds of lines don't: what the tool itself covers, and the one-line summary of your result. The step-by-step checklist names the form and line, or points you to the reporting guide for that year.
What answers can a tool give?
One of four: eligible, not eligible, need more information, or outside what this tool covers. A tool never guesses a fact you didn't give it. It doesn't say "eligible" by default.
How are the tools tested?
Every tool is tested before each update to the site. The tests check birthdays and leap days. They check the exact dollar limit, and one dollar over it. They check every type of account and every type of charity the checker knows, in one list the tests read. They check missing and bad answers too. If a test fails, the site does not update.
Is what I type into a tool saved or sent anywhere?
No. The tools run only on your device. Nothing you type is sent to a server. It isn't saved, and it isn't put in the page address.
When the QCD checker gives an answer, Google Analytics counts which of the four kinds of answer it was. That is the only thing analytics gets from the tool — it never gets what you typed. If you type your email into the newsletter form, that address goes to our email service. The privacy page explains what analytics records.
What don't the tools cover?
The tools follow federal law for the tax years they list. They don't cover state taxes. See the disclosures for what the tools can't do.