The aguinaldo: how Mexico's mandatory Christmas bonus works in payroll

Every employer in Mexico owes each worker an aguinaldo of at least 15 days of salary, and it has to be paid before 20 December each year (LFT Art. 87). This is not a discretionary bonus or a performance reward. It is a statutory entitlement with a fixed deadline, and the 15 days is the floor, not the number most workers actually receive. Many employers pay 20, 30, or more days by contract or collective bargaining agreement. Whatever the contractual figure, the law will not accept less than 15 days, and it will not accept payment after 20 December.

This article walks through how the aguinaldo is calculated and taxed: the 15-day minimum and the December deadline, how the amount is prorated for a worker who did not stay the full year, which wage the calculation is based on, and how the income-tax exemption is applied.

The 15-day floor and the December deadline

The rule in Art. 87 is short. Workers are entitled to an annual aguinaldo, payable before 20 December, equal to at least 15 days of salary. A worker on a fixed monthly wage of MXN$30,000 has a daily wage of MXN$1,000 (MXN$30,000 divided by 30), so 15 days of salary is MXN$15,000. That is the statutory minimum aguinaldo for a full-year employee at that wage.

The 20 December date is a hard deadline, not a target. A late or missing aguinaldo exposes the employer to fines and to labor-court claims for the unpaid amount. Because the calculation itself is simple, most disputes are not about the arithmetic. They are about employers who paid the wrong base, who forgot a worker who left in October, or who missed the date.

Proration: partial-year workers, including leavers

A worker who did not work the full calendar year is entitled to the proportional part of the aguinaldo, for the time actually worked. Art. 87 is explicit that this applies whether or not the worker is still employed on the payment date. A person who resigned or was dismissed in September is still owed their share for January through September, and that share is paid as part of the final settlement rather than in December.

The proration is straightforward in words: take the full 15-day aguinaldo, then multiply by the days the person worked in the year divided by 365. A worker on the same MXN$1,000 daily wage who worked 200 days of the year is owed 15 days times (200 divided by 365) times MXN$1,000, which is MXN$8,219.18. The worker who leaves mid-year is the case employers most often miss, because that entitlement is settled months before December and is easy to overlook once the person has gone.

Which wage the aguinaldo is based on

The aguinaldo is calculated on the daily wage (the cuota diaria), the ordinary wage the worker earns for the work. For a salaried employee this is the monthly salary divided by 30. It is not the higher integrated figure used for severance, which folds in the proportional value of benefits; the aguinaldo base is the plain daily wage.

Variable pay changes the base. For a worker paid partly or wholly on commission or piecework, the daily wage is an average: Art. 89 sets it as the average of earnings over the 30 days actually worked before the entitlement arises, and for a worker employed all year the annual average of earnings is commonly used. Commissions and regular variable earnings belong in that average. Basing a commission-earner's aguinaldo on their fixed salary alone, and leaving the commissions out, understates the amount and is a frequent source of claims. A salesperson with a MXN$12,000 monthly base and MXN$8,000 in average monthly commissions has an aguinaldo base of MXN$20,000 a month, not MXN$12,000.

Tax: the aguinaldo is taxable, minus 30 days of UMA

The aguinaldo is taxable income, but income tax law exempts part of it. Under LISR Art. 93, section XIV, the aguinaldo is exempt up to the equivalent of 30 days of the UMA, and only the amount above that is subject to income tax (ISR) withholding.

The UMA (Unidad de Medida y Actualización) is the reference unit Mexico uses in place of the minimum wage for this exemption, following the 2016 constitutional reform. INEGI sets its value annually, effective 1 February. For the period from 1 February 2026, the daily UMA is MXN$117.31 (INEGI, published in the Diario Oficial on 9 January 2026). Thirty days of UMA is therefore MXN$3,519.30. That figure is the exempt portion of every worker's aguinaldo in 2026, and it is the same amount for everyone regardless of salary. A higher-paid worker does not get a larger exemption; a larger share of their aguinaldo simply falls into the taxable portion.

For the worker earning MXN$1,000 a day, the aguinaldo of MXN$15,000 breaks down as follows. The first MXN$3,519.30 is exempt. The remaining MXN$11,480.70 is the taxable portion, and ISR is withheld on that part only.

There is a second layer in the withholding itself. A lump sum like the aguinaldo, added to the month's ordinary salary, can push the combined pay into a higher bracket than the worker's steady income would occupy, so the withholding overstates the real tax. RLISR Art. 174 provides an optional method that avoids this: it spreads the taxable aguinaldo across the year to find the marginal rate the worker would bear if the amount had been earned evenly, and applies that rate to the taxable portion. The result is a withholding closer to the worker's true annual rate rather than the inflated single-month rate. The method is optional, but for a large aguinaldo it prevents a real over-withholding: without it, the worker has tax deducted in December that they only recover later on the annual return.

A worked example, end to end

Take a full-year employee on a fixed monthly salary of MXN$30,000.

• Daily wage: MXN$30,000 divided by 30 = MXN$1,000.
• Aguinaldo, 15 days: MXN$1,000 times 15 = MXN$15,000.
• Exempt portion, 30 days of UMA: 30 times MXN$117.31 = MXN$3,519.30.
• Taxable portion: MXN$15,000 minus MXN$3,519.30 = MXN$11,480.70.

The worker's gross aguinaldo is MXN$15,000. ISR is withheld only on MXN$11,480.70, and the RLISR Art. 174 method sets the rate on that amount. The MXN$3,519.30 is paid free of income tax. Change the salary and only the taxable portion changes; the exempt MXN$3,519.30 stays fixed for every worker in 2026.

Four recurring aguinaldo pitfalls: deadline, leavers, variable pay, exemption

Four things about the aguinaldo need attention every year:

• The 20 December deadline. It is fixed by law and enforced. The payment has to reach the worker before that date, not merely be calculated by then.
• Leavers. Anyone who worked part of the year is owed the proportional aguinaldo, settled when they leave. These entitlements fall due long before December and are the ones most often missed.
• The base for variable pay. Commission and piecework earners are entitled to an average that includes their variable earnings, not their fixed salary alone. Leaving commissions out understates the aguinaldo.
• The exemption value. The 30-day UMA exemption is recalculated every February when INEGI publishes the new UMA. An aguinaldo run in December 2026 uses the MXN$117.31 value; the following year uses whatever INEGI sets next. Using last year's figure quietly understates the tax withheld.

None of this is hard for a single worker. The demand is volume: a payroll team applies every rule at once, across a whole book of clients, in the same tight December window, against a UMA value that changed back in February. Flux keeps the deadline, the proration, the wage base, and the current exemption applied on every run, so December is an ordinary pay cycle rather than an annual reconstruction from last year's spreadsheet.