Checked, and what is not.

What the checks are

• Reference cases. A few inputs together with the answer worked out another way: an exact definition (a metre is exactly 100 centimetres), a published worked example, or a hand calculation written out in full. Each case states how closely the tool must agree and where the answer came from. The build runs every case through the real engine; if one does not reproduce, the page that would have shown it is not built.
• Golden snapshots. The exact default result of a tool is stored in the project’s tests. If an engine starts giving a different answer, the tests fail until a person has looked at what changed and updated the snapshot on purpose. 758 tools are pinned this way. Tools that need a browser (images, PDFs, files, live feeds) cannot run in the test suite and are not pinned.
• Check a number. A way to test an answer you were given by anyone, including an AI assistant. See below.

What this does not say

• A passing check shows that the engine reproduces values worked out independently for those cases. It does not prove every possible input gives the right answer, and it cannot tell you whether a tool’s method suits your situation.
• A tool without a check is not marked wrong, and a tool with one is not certified. Some tools without reference cases here are covered by independent test vectors inside the project’s own tests (probability tables and calendar fixtures, for example). They are not counted on this page, because it only shows checks it can run and display.
• The date is when the site was built. A deployment that is out of date shows an older date, which is the honest thing for it to show.

Check a number you were given

Been handed an answer, perhaps by an AI assistant, and want to know whether Toolmoz agrees? Open the tool, enter the same inputs, then use Check a number under the result and type the answer. Toolmoz compares it with what the tool computes, to the precision you wrote, and tells you the difference if there is one. It runs on your device; the number is not sent anywhere.

The same check can travel in a link. Add expect= (and, if a tool gives several results, expectm= with the result’s name) to the link’s # part:

• Percentage change from 80 to 100, claimed 25: matches.
• The same inputs, claimed 0.25: does not match, and Toolmoz points out that the claim is 100 times smaller than a result.

A match means the number equals one of the tool’s results at the precision you gave (25 is read as “to the nearest whole number”, 25.30 as “to two decimal places”). It checks the arithmetic for the inputs in the form. It cannot tell whether those inputs are the right ones, so look at them as well. “Copy a prompt for your assistant” puts a request on your clipboard that asks the assistant to run the calculation and report Toolmoz’s number, rather than agree with yours.

Coverage by category

Tools with reference checks (182)

Each tool page shows its cases under “How this is checked”. Open a category to list them.

Tools without reference cases yet (661)

New tools must carry reference cases, and the project’s tests only allow this list of older tools to shrink. Some tools will always be exempt, for a stated reason (image and file tools, random draws, live data).