Mexico's IMSS employer contribution splits across seven distinct branches, not one flat percentage, and one of them behaves completely differently from every other line item on this site: the cuota fija within Enfermedades y Maternidad is priced against a fixed government reference value (the UMA), not the employee's own salary. Whether you're hiring at minimum wage or a six-figure USD-equivalent salary, that one component costs exactly the same.
CEAV (Cesantía y Vejez) is the opposite, it scales with salary through UMA-denominated bands, and it's also on a legislated upward trajectory through 2030 as part of a pension reform, meaning this exact calculator's numbers will need updating again next year even if nothing else changes.
Layer INFONAVIT and Riesgos de Trabajo on top of IMSS (both share IMSS's wage cap), then ISN, a genuinely separate state-level tax with no ceiling at all, and finally the mandatory aguinaldo, a real annual cash outlay, and you get a picture that's meaningfully more complex than a single "employer pays X%" headline figure would suggest.