The Real Cost of a Mexican Hire: Employer Contributions, IMSS, and Payroll Taxes

The salary you agree with a worker in Mexico is not what that worker costs you. On top of gross wages sit several employer-only obligations: social-security contributions across several branches, a housing contribution, a state payroll tax, and a set of statutory benefits the law requires you to pay whether you planned for them or not. Added up, these charges come to somewhere in the region of 25 to 35 percent on top of wages for a typical worker, and most of the total never appears on the employee's payslip, because the employer pays those amounts rather than deducting them from the worker. If you are budgeting the cost of a hire in Mexico, or running payroll for someone who is, the number that matters is the fully loaded one, and understanding how it is built is the difference between pricing a role correctly and discovering the true cost after you have already committed to it.

Let me go through these in order: the base they are all calculated on, then IMSS branch by branch, then the risk premium that behaves differently from everything else, then the costs beyond IMSS, and finally what the total comes to.

The base: the SBC

Almost every contribution in this guide is calculated on the same figure, the Salario Base de Cotización, the SBC. It is the worker's integrated daily wage: base pay plus the proportional value of benefits like the aguinaldo and vacation premium, expressed per day. It is not the same as gross pay, and it is the single most important number in Mexican payroll because so many charges scale off it.

Two boundaries matter. The SBC is capped at 25 times the UMA, the Unidad de Medida y Actualización, which for 2026 is MXN$117.31 a day, so the ceiling on the daily SBC is about MXN$2,933. Above that, contributions stop climbing. And a threshold of 3 UMA (about MXN$352 a day in 2026) marks where one health sub-branch begins to apply. Keep those two numbers in mind, because they shape the whole calculation.

IMSS, branch by branch

IMSS, the Instituto Mexicano del Seguro Social, is the public social-security system, and employer contributions to it are not a single percentage. They are split across several insurance branches (seguros), each with its own rate and its own logic, and the employer pays the large majority of the total. Here is the employer side for 2026, all calculated on the SBC unless noted.

A few of these deserve a word, because they do not behave the way a flat percentage would.

The cuota fija for health is the one that surprises people. It is a fixed charge of 20.40 percent of one UMA per worker, regardless of what the worker earns, about MXN$728 a month in 2026. Because it is a flat per-head amount rather than a percentage of pay, it is regressive: it is a large proportion of the cost of a low-wage worker and a trivial one for a high earner. An employer with a workforce of minimum-wage employees feels this charge far more, proportionally, than one employing specialists.

The Enfermedades y Maternidad branch then adds three percentage components on top of the cuota fija: a 1.10 percent excedente that applies only to the part of the SBC above 3 UMA, a 0.70 percent cash-benefits component, and a 1.05 percent component for the medical costs of pensioners, all on the employer side. Workers contribute to health too, but at much smaller rates; the employer pays the bulk.

Invalidez y Vida (disability and life) is a straightforward 1.75 percent on the employer. Guarderías y Prestaciones Sociales (daycare and social benefits) is 1.00 percent and is entirely employer-funded; workers pay nothing toward it. And Retiro (the 2 percent retirement contribution) is likewise 100 percent employer-paid, which is a common source of error: it is not deducted from the worker, and it should never appear on the employee's side of the ledger.

Cesantía y Vejez (severance-at-old-age and old age), the main retirement branch, is the one that has been rising. Under the 2020 pension reform, the employer's contribution to this branch is being raised in steps through 2030, and it is progressive: it rises with the worker's SBC, from 3.150 percent at the minimum wage up to 7.513 percent for workers earning above roughly 4 UMA. The worker's own contribution to this branch stays fixed at 1.125 percent regardless of pay. So for higher earners, Cesantía y Vejez has become one of the largest single lines in the employer's contribution bill, and it is still rising year over year until the phase-in completes.

That leaves Riesgos de Trabajo, which is different enough to need its own section.

Riesgos de Trabajo: the contribution your safety record controls

Every other IMSS branch is a rate you look up. Riesgos de Trabajo, the work-risk insurance, is a rate you partly earn, and it is entirely on the employer. It funds the benefits paid when a worker is injured, disabled, or killed on the job, and it is the one contribution where your own behavior moves the number.

The risk premium starts with classification. Every employer is assigned to one of five risk classes based on its activity, with a base rate (the prima media) that runs from Class I at 0.54355 percent for office work, software, and financial services, up through Class II at 1.13065 percent for retail and light assembly, Class III at 2.59840 percent for transport and food processing, Class IV at 4.65325 percent for construction and heavy manufacturing, and Class V at 7.58875 percent for mining and hazardous work. The gap between the ends is enormous: on the same payroll, a Class V employer pays roughly fourteen times what a Class I employer pays for this one branch. Getting the classification right matters, and a common audit finding is a mixed workforce misclassified downward, for example a staffing firm that places mostly office workers but a few in construction and has to apply the higher class.

Then comes the part that makes this a genuine cost lever rather than a fixed charge: experience rating. Each year, an employer recalculates its own risk premium using a formula based on its siniestralidad, its accident history over the prior year, counting the days workers lost to injuries, the permanent disabilities, and any deaths, relative to the size of the workforce. A clean safety record pushes the premium down; a bad year pushes it up. The recalculated premium is filed with IMSS by the end of February each year and applies for the following twelve months. There are guardrails: the premium can never go below 0.50 percent or above 15.00 percent regardless of class, and it cannot move by more than one percentage point in a single year, so a company sitting at 2 percent cannot be jolted to 5 percent overnight. But over a few years, safety performance genuinely changes what a company pays, which is the whole design intent. For payroll, this means the risk premium is not a set-and-forget rate; it has to be recomputed and refiled annually, and the number you used last year is very likely not the number you use this year.

Beyond IMSS: housing, state payroll tax, and statutory benefits

IMSS is the largest part of the employer's cost, but not the whole of it.

INFONAVIT adds a 5 percent employer contribution on the SBC into each worker's housing subaccount. It uses the same SBC and the same 25 UMA ceiling as IMSS, and like the retirement contributions it is remitted on the bimonthly cycle. It is an employer cost, never a deduction from the worker, and for most workforces it is one of the bigger single lines after Cesantía y Vejez.

ISN, the Impuesto Sobre Nóminas, is the state payroll tax, and it is the one employer cost here that is not federal. Each of Mexico's 32 states sets its own rate, generally in the range of 1 to 4 percent of total payroll, and several states have been raising it. It is calculated on payroll rather than on the SBC, it is entirely an employer cost, and because it varies by the state where the work is performed, a company operating in several states pays several different rates at once.

Then there are the statutory benefits, which are not contributions but are just as much a cost of employment because the law requires them. The aguinaldo, the year-end bonus, is a minimum of 15 days of wages. Paid vacation includes a vacation premium of at least 25 percent of the wages for those days, and since the 2023 vacation reform the vacation entitlement itself starts higher, at 12 days in the first year. Workers who work Sundays are owed a Sunday premium of 25 percent. And profit sharing, the PTU, obliges most employers to distribute 10 percent of taxable profits to workers each year, subject to a cap of three months' salary or the average of the last three years' PTU, whichever favors the worker. Spread across the year, these benefits add several more points to the true cost of a hire on top of the contribution rates.

The total employer cost

Let me run a worker through the full calculation. Take someone with an SBC of MXN$1,000 a day, roughly MXN$30,400 a month, which sits well above the 3 UMA threshold and below the 25 UMA ceiling, at a Class I office employer. The employer's monthly IMSS and INFONAVIT contributions come out roughly as follows: about MXN$728 for the health cuota fija, around MXN$217 for the excedente, MXN$213 for cash benefits, MXN$319 for pensioners' medical costs, MXN$532 for disability and life, MXN$304 for daycare, MXN$608 for retiro, about MXN$2,284 for Cesantía y Vejez at the top progressive rate, around MXN$165 for the Class I risk premium, and MXN$1,520 for INFONAVIT. That is roughly MXN$6,890 a month, about 23 percent of the SBC, before the state payroll tax. Add ISN at, say, 3 percent, and you are near 26 percent. Layer in the amortized cost of the aguinaldo, vacation premium, and profit sharing, and the fully loaded figure reaches the low-to-mid 30s percent above wages.

Two features of that arithmetic are worth internalizing. First, the mix shifts with pay: for a low earner, the flat health cuota fija is a heavy proportional load and the progressive retirement rate is at its lowest, while for a high earner the cuota fija fades to insignificance and Cesantía y Vejez becomes the dominant line. There is no single "employer rate" in Mexico; the effective percentage depends on where the worker sits on the SBC scale. Second, several of the inputs change every year: the UMA resets each February and rescales the ceiling, the cuota fija, and the thresholds; the Cesantía y Vejez employer rate is still rising under the pension reform through 2030; the risk premium is recalculated annually from your accident record; and several states keep raising ISN rates. A cost model built on this year's numbers is not a cost model for next year.

Paying it, and getting it right

The mechanics reinforce the point. IMSS ordinary branch quotas are determined and paid monthly, while the retirement (RCV) and INFONAVIT contributions run on the bimonthly cycle, all calculated through the Sistema Único de Autodeterminación (SUA) and generally due by the 17th. The risk-premium recalculation is filed separately, once a year, by the end of February. Because IMSS and INFONAVIT collect as fiscal authorities, a late or short payment does not draw a polite reminder; it accrues inflation adjustments and surcharges, and can be enforced.

So the cost of employing someone in Mexico is a set of employer charges calculated on the SBC, not a salary with a single fixed percentage added on top. Most of those charges are paid by the employer on top of wages rather than deducted from the worker, they vary by the worker's pay level and the employer's state and risk class, and their rates change on their own annual schedules. Flux keeps this calculation current: the branch rates, the progressive Cesantía y Vejez schedule, the UMA-driven ceiling and cuota fija, the per-state ISN, and the annually refiled risk premium, so each period uses the current employer cost, not last year's. In Mexico, the salary is the easy part. The employer contributions, payroll taxes, and statutory benefits added on top are the larger and less visible part of the cost of hiring an employee, and an employer should know that full figure to the peso before hiring, not after.