How this is made

The three places a number here can come from

First: the reader typed it in. Every tool takes its quantities from the form, which is why none of them can originate an amount.

Second: it is printed on the barrel. The five calibrations, their capacities and their graduation intervals are properties of manufactured objects, visible to anybody holding one, and they are the only facts about the physical world this site asserts.

Third: it was computed, at build time, by the same functions the live tools call. Every figure in every table on the barrel pages and the vial pages is generated that way, so a table cannot disagree with the tool it should match.

What this site refuses to hold

Compound data of any kind. No names, no molar masses, no potencies, no half-lives, no typical anything. Where a tool needs one of those figures - the molar amount tool needs a molar mass, the international units tool needs a potency - it asks for it and says what kind of source that figure belongs to.

A built-in table of such figures would be a claim about a vial this site has never seen, maintained by nobody and checked by nobody. A field is more honest than a stale lookup.

How the arithmetic is checked

The calculation engine is dependency-free, has no network access and holds no data. It is covered by a unit test suite, and by mutation testing: a harness introduces deliberate defects into the engine one at a time - an inverted ratio, a multiply where a divide belongs, a wrong unit factor, a safety label that overstates what is known - and fails if the test suite does not notice.

A separate suite runs over the built site and checks the properties that cannot be unit tested: that every page carries the disclosure sentences, that every table cell matches the tool, that no internal link points at a page that was not built, and that no amount is stated for anyone.

None of that is clinical review. It is evidence that the software does what it says, which is a different claim and a smaller one.

The review date in the footer

The date at the foot of every page is the date a committed data snapshot was last matched against its sources. It is a real event, recorded in a file in the repository, rather than today's date printed to look fresh.

A stamp that moves on every build is a build timestamp wearing a review date's clothes, and it tells a reader nothing. This one does not move unless something was actually checked.