Written for Mexico. This analysis applies to Mexican federal tax law — ISR (income tax), IVA (VAT) and SAT rules — and cites Mexican statutes. Amounts are in Mexican pesos (MXN).
Between the salary you agree on and what that worker actually costs you sits a layer many employers discover too late: the employer-employee social security contributions (cuotas obrero-patronales) — the tripartite financing (employer, worker, government) of social security. They are not "one more tax": they are several distinct types of insurance, each with its own rate, its own base and its own logic. Here is the full teardown — and for your exact numbers, our total cost of an employee calculator runs them in seconds.
The base of it all: the base contribution salary
Contributions are not calculated on the nominal salary but on the SBC (salario base de cotización, the base contribution salary): the daily wage integrated with the aguinaldo (the mandatory Christmas bonus), vacation premium and every regular benefit the worker receives (the statutory minimums produce an integration factor of ~1.0452 in the first year, which grows with seniority through vacation days). Upper cap: 25 UMA (the UMA being the daily reference unit; ~$2,933 a day in 2026). The two cardinal sins live here: under-integrating (leaving out regular bonuses and benefits — guaranteed adjustments in an audit) and the classic fraud of registering a salary below the real one, which, on top of its legal consequences, robs the worker of pension and Infonavit (housing fund) credit — something they now spot in two clicks on their weeks-of-contribution statement.
The branches, and who pays each one
The employer's (the heavy part): sickness and maternity (a fixed contribution per worker of 20.40% of the UMA — paid even on a minimum-wage salary — plus the excess above 3 UMA and the benefits branches), occupational risk (your premium by class and accident history, from ~0.5% to 15% of the SBC — the branch where safety management turns into money), disability and life (1.75%), daycare (1%), retirement 2% + the employer's cesantía (advanced-age unemployment) and old-age share — the latter rising each year under the pension reform according to salary level (in 2026, between ~3.15% and ~7.51% of the SBC — the year's table is in the Annex to the LSS) — and Infonavit 5%. The worker's (withheld from payroll): ~2.375% in the sickness/disability branches plus 1.125% of cesantía — the employer withholds and remits; if it does not withhold, it absorbs. The government's: the social contribution and allocations to specific branches.
How much it adds up to — and when it's due
2026 rule of thumb: the full employer charges (IMSS + RCV + Infonavit, not counting the ~3% state payroll tax, or ISN) typically add on the order of 15% to 25%+ on top of the salary, proportionally heavier on low salaries (the fixed contribution weighs more) and where the risk premium is high. A $20,000 salary with statutory benefits costs the employer around $24,000 including social charges and state tax — run your case in the calculator with your state and your risk class. Payment: monthly by the 17th (IMSS) and every two months (RCV+Infonavit), with the SUA→SIPARE mechanics that have their own guide.
Do you know what your payroll really costs you — and how much of that is legally optimizable?
The compensation structure has legitimate room: well-designed social-welfare benefits, correct integration (neither too much nor too little), a managed risk premium, and the market's gray schemes ruled out on solid grounds (the payroll 'savings' being sold today are tomorrow's labor-tax-criminal liability). The payroll diagnostic compares your current cost against the optimal, legal structure — with numbers, not promises.
Frequently asked questions
Can I agree on a 'net salary' so the worker 'doesn't contribute'?
No — registration and contribution are non-waivable employer obligations: any agreement to the contrary is void, and the liability (omitted contributions with their accessory charges, capitales constitutivos — an accident's full cost billed to the employer — if one occurs, and the criminal route in extreme cases) is yours. The 'trusted employee who preferred more take-home pay' turns into a lawsuit with their first illness.
Are the contributions I pay deductible?
The employer share, yes, fully. The employee share that the employer absorbs for minimum-wage workers, too; voluntarily absorbing it at other levels has its own treatment. Together with stamped payroll (payroll certified through the SAT), they are among the cleanest deductions there are — when the payroll CFDI (the digital tax invoice) and the payments reconcile.
I have asimilados and independent contractors — do they generate contributions?
They do not generate IMSS contributions on their own — precisely because they are not an employment relationship. The risk is the disguise: the 'asimilado' (salary-assimilated payee) or 'contractor' with real subordination is an unregistered worker, and the IMSS recharacterizes with pleasure (audits, inspections and labor lawsuits are the three doors). The real nature of each relationship is the only safe boundary.
Let's talk about your case
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