About

CALX gathers 104 scientific calculators and converters, free and without any account, from high school to the laboratory. One principle governs them all:a result is only worth what its origin can prove.

Every tool shows its work

The applied formula is displayed with your values injected into it, not just the result. Each tool's dossier states the definitions, the domain of validity and the model's assumptions: what the calculation assumes, and what it does not cover.

Sources are cited, or the math is exact

Tools rest either on exact closed-form mathematical relations, or on constants and data from primary sources (SI definitions, IUPAC atomic weights, articles and datasheets cited with their precise reference and consultation date). No value is copied from a third-party site without tracing it back to its origin.

Verdicts are honest

When a question has no answer, the tool says so: an object at a lens focus gives "image at infinity", not a very large number; an impossible triangle is refused, not approximated; a yield above 100% is flagged as an anomaly, never rounded down to 100. What is not determined reads "not determined".

Everything is checked against witnesses

Every tool is covered by tests confronted with independent witnesses: published table values, mathematical identities recomputed on every result (mass conservation, Kirchhoff's voltage law, Lagrange's identity…), and boundaries tested on both sides. More than 3,400 tests guard the catalogue, and no page ships unless they pass.

Your data stays with you

Calculations run in your browser. Nothing you type is transmitted: see theprivacy policy.