UMA in Mexico, 2026: what it is worth and how it shapes your payslip
If you have just started working in Mexico, the UMA is the acronym nobody explains. It decides how much of your year-end bonus is tax-free, where your social security contributions stop and how much severance escapes tax. Here it is in pesos for 2026.
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The UMA (Unidad de Medida y Actualización, unit of measure and update) is the peso amount Mexican federal law uses to set fines, caps and tax exemptions, a role that used to belong to the minimum wage. INEGI, the national statistics office, set it for 2026 at MX$117.31 a day, MX$3,566.22 a month and MX$42,794.64 a year, 3.69 % more than in 2025, in force from 1 February 2026. On a payslip it limits the tax-free part of the aguinaldo year-end bonus to 30 UMA, the vacation premium and profit sharing to 15 UMA each, and severance to 90 UMA per year of service, under article 93 of the Income Tax Law. It also caps IMSS social security contributions at 25 UMA a day. Because these limits do not rise with salary, they matter less the more you earn.
Convert UMA to pesos
In pesos (daily UMA)
MX$3,519.30
| Monthly UMA | MX$106,986.60 |
| Annual UMA | MX$1,283,839.20 |
| With the 2025 UMA | MX$3,394.20 |
Where the UMA appears in your pay
The UMA is never paid to anyone. It is a yardstick: laws say «30 UMA» or «25 UMA» instead of a peso amount, and the peso figure moves each year without the law being rewritten. Unless a rule says otherwise, it means the daily value. These are the payroll rules that depend on it in 2026.
| Rule | Measured as | Pesos in 2026 |
|---|---|---|
| Tax-free part of the aguinaldo (year-end bonus), per year | 30 × daily UMA | MX$3,519.30 |
| Tax-free part of the vacation premium, per year | 15 × daily UMA | MX$1,759.65 |
| Tax-free part of PTU profit sharing, per year | 15 × daily UMA | MX$1,759.65 |
| Tax-free severance, per year of service | 90 × daily UMA | MX$10,557.90 |
| IMSS contribution ceiling, per day | 25 × daily UMA | MX$2,932.75 |
| IMSS surcharge threshold, per day | 3 × daily UMA | MX$351.93 |
| Employment subsidy, per month | 15.02% of monthly UMA | MX$535.65 |
A smaller one matters in retail and hospitality: Sunday premium (prima dominical) is exempt up to one UMA per Sunday worked, MX$117.31 in 2026.
Bonuses on a professional salary: the cap is fixed, the bonus is not
Mexican law requires an aguinaldo of at least 15 days’ pay before 20 December, and a vacation premium of at least 25 % of vacation pay. Both are partly tax-free, but the exempt slice is a fixed number of UMA, the same for every worker. On a salary of MX$90,000 a month:
- The legal-minimum aguinaldo is MX$45,000. Only MX$3,519.30 is exempt, so MX$41,481 is taxable and adds around MX$12,946 of ISR in December under the general method.
- The vacation premium after two years of service is MX$10,500, of which at most MX$1,759.65 escapes tax.
For a minimum-wage worker the same caps cover the whole bonus. That asymmetry is deliberate: the exemptions protect low pay, not executive packages. If your contract was drafted abroad and promises a «13th month», check whether it is meant to replace the aguinaldo or come on top of it. The aguinaldo calculator splits any bonus into its exempt and taxable parts.
The IMSS ceiling for high earners
IMSS, the Mexican Social Security Institute, deducts the employee share of health, disability, retirement and old-age insurance from the integrated daily wage (salario base de cotización). That base cannot exceed 25 UMA, MX$2,932.75 a day in 2026. Above 3 UMA (MX$351.93) an extra 0.40 % health surcharge applies to the difference. Many expatriate salaries are well above the ceiling, which is why their IMSS line looks small next to ISR.
Do you reach the IMSS contribution cap?
Monthly IMSS contribution
MX$2,431
| Calculated SBC | MX$3,147.95 |
| Cap (25 UMA) | MX$2,932.75 |
| Cap reached? | Yes |
The simulator converts monthly pay into an integrated daily wage with the legal minimum benefits. Generous benefits raise the integrated wage, so you hit the cap sooner. Foreign nationals working for a Mexican employer are enrolled with IMSS like anyone else; the IMSS calculator shows each branch of the deduction.
Severance and the UMA
When employment ends, indemnities, the seniority premium and other separation payments are exempt up to 90 UMA for each year of service, counting more than six months as a full year. Two years of service shelter MX$21,115.80, four years MX$42,231.60, ten years MX$105,579.00. The taxable remainder is taxed at the rate that results from your last ordinary monthly salary, not at the top bracket. For the full package after a dismissal, see the severance pay calculator; for a resignation, the finiquito calculator.
2026 values and the January gap
| UMA | Value |
|---|---|
| Daily, 2026 | MX$117.31 |
| Monthly, 2026 (daily × 30.4) | MX$3,566.22 |
| Annual, 2026 (monthly × 12) | MX$42,794.64 |
| Daily, 2025 (used until 31 January 2026) | MX$113.14 |
| Increase over 2025 | 3.69 % |
INEGI publishes the new UMA in January, indexed to the previous year’s inflation, and it applies from 1 February. Payments made in January 2026 therefore used the 2025 value, which gives slightly smaller exemptions. The calculators on this site use the 2026 value, valid from February to December, so for a January payment their exempt figures are a little generous.
UMA versus the minimum wage
Mexico decoupled its legal references from the minimum wage so that raising the minimum would no longer inflate every fine and cap in federal law. Since then the two have drifted apart: in 2026 the general minimum wage rose 13 % to MX$315.04 a day, while the UMA rose 3.69 %. Some payroll rules still use the minimum wage, not the UMA: no ISR is withheld from a worker paid only the minimum, the IMSS base can never be lower than the minimum of the zone, and the seniority premium is calculated on pay capped at twice the minimum. The minimum wage guide has those figures.
One practical tip for anyone reviewing a Mexican payslip or offer letter: when an amount is described as exempt, look for a round multiple of MX$117.31. If it is a multiple of MX$315.04 instead, the payroll system is applying a rule that no longer exists.