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Mexico Isr Aguinaldo Calculator

Free mexico isr aguinaldo calculator — instant accurate results with step-by-step breakdown. No signup required.

⚡ Free to use 📱 Mobile friendly 🕒 Updated: June 06, 2026
🧮 Mexico Isr Aguinaldo Calculator
ISR a Retener
$0.00
Aguinaldo Neto: $0.00
📊 Aguinaldo Neto vs ISR Retenido por Nivel Salarial (México 2024)
📋 Table of Contents
  1. Use the Mexico Isr Aguinaldo Calculator
  2. What is Mexico Isr Aguinaldo Calculator?
  3. How to Use
  4. Formula Used
  5. Example Calculation
  6. Benefits
  7. Tips and Tricks
  8. Conclusion
  9. FAQ (8 Questions)

What is Mexico Isr Aguinaldo Calculator?

A Mexico ISR Aguinaldo Calculator is a specialized financial tool designed to compute the exact Income Tax (ISR) withholding on the mandatory year-end bonus (Aguinaldo) that employers in Mexico must pay to their workers. Under the Mexican Federal Labor Law (Ley Federal del Trabajo), every employee is entitled to at least 15 days of salary as an Aguinaldo, paid on or before December 20th each year. This free online calculator instantly determines the taxable portion of that bonus and calculates the precise ISR withholding based on the current tax tables published by the Servicio de Administración Tributaria (SAT).

Human resources professionals, payroll administrators, accountants, and individual employees rely on this tool to ensure accurate tax compliance and avoid costly errors during the high-volume year-end payroll season. For workers, understanding the ISR on their Aguinaldo helps them plan their December finances, as the net bonus they receive can be significantly lower than the gross amount due to mandatory tax withholdings. For employers, miscalculating the ISR can lead to fines, interest charges, and legal disputes with employees.

This free Mexico ISR Aguinaldo Calculator eliminates guesswork by using the most current annual tax tables and applying the correct calculation methodology, including the critical concept of the "Aguinaldo exemption" — the first 30 days of the minimum daily wage (UMA) which are tax-free. No signup, login, or personal data is required to get instant, accurate results with a full step-by-step breakdown of how the tax was computed.

How to Use This Mexico Isr Aguinaldo Calculator

Using this free online tool is straightforward and takes less than one minute. The calculator is designed for both employers running bulk payroll calculations and individual employees who want to verify their year-end bonus. Follow these five simple steps to get an accurate ISR withholding calculation for any Aguinaldo amount.

  1. Enter Your Gross Aguinaldo Amount: In the first input field, type the total gross amount of your Aguinaldo before any taxes or deductions. This should be the full bonus calculated based on your daily salary multiplied by at least 15 days. For example, if your daily salary is $500 MXN and you are entitled to 15 days, enter $7,500 MXN. If your employer gives more than the legal minimum (some companies offer 20, 30, or even 40 days), enter that full amount.
  2. Select Your Payroll Period (Optional but Recommended): Choose whether you are paid weekly, bi-weekly, or monthly from the dropdown menu. This selection is important because the ISR calculation method for Aguinaldo uses the tax table that corresponds to your regular payroll frequency. If you are unsure, monthly is the most common selection for salaried employees in Mexico and works correctly for the vast majority of cases.
  3. Enter Your Monthly Gross Salary: Input your regular monthly gross salary (before any deductions) in the designated field. This figure is critical because the calculator must combine your Aguinaldo with your regular December salary to determine your total income for the month, then calculate the tax on the combined amount, and finally subtract the tax already withheld on your regular salary. For weekly or bi-weekly employees, the calculator automatically converts your salary to a monthly equivalent using the standard conversion factors (4.33 weeks per month).
  4. Click "Calculate ISR": After entering all required information, click the prominent "Calculate ISR" button. The calculator immediately processes your data using the official SAT tax tables for the current fiscal year. The calculation applies the exemption (30 days of UMA), determines the taxable portion of the Aguinaldo, and computes the marginal tax rate applicable to that additional income.
  5. Review Your Detailed Results: The results page displays several key figures: your gross Aguinaldo amount, the exempt portion (tax-free), the taxable Aguinaldo amount, the ISR withholding amount, and your net Aguinaldo (take-home bonus). A complete step-by-step breakdown shows exactly how each number was derived, including which tax bracket was applied and the exact calculation formula used.

For best accuracy, always use your exact daily salary (not an average) and confirm your payroll period with your HR department. The calculator automatically updates to reflect the latest UMA values and tax table adjustments published by SAT each year.

Formula and Calculation Method

The ISR calculation on Aguinaldo in Mexico follows a specific methodology mandated by the Ley del Impuesto Sobre la Renta (LISR). Unlike regular salary ISR which is calculated using the monthly tax table directly, the Aguinaldo ISR uses a "cash flow" or "accumulation" method. This means the calculator first determines the tax on your total December income (salary + Aguinaldo), then subtracts the tax already withheld on your regular salary. The difference is the ISR due on the Aguinaldo. This method prevents double taxation and ensures you only pay the marginal rate on the additional bonus income.

Formula
ISR on Aguinaldo = ISR on (Monthly Salary + Taxable Aguinaldo) − ISR on Monthly Salary Only

Where: Taxable Aguinaldo = Gross Aguinaldo − Exempt Portion
Exempt Portion = 30 × Daily UMA Value

The variables in this formula are critical to understand. The "Monthly Salary" is your gross pay for the month of December, including all regular earnings. The "Taxable Aguinaldo" is the portion of your bonus that exceeds the legal exemption. The "ISR on Monthly Salary Only" represents the tax that would be withheld on your regular paycheck without the Aguinaldo. The "Daily UMA Value" is updated annually by INEGI and is the basis for the tax exemption calculation. For 2024, the daily UMA is approximately $108.57 MXN, making the exempt portion around $3,257.10 MXN. Any Aguinaldo amount above this threshold is subject to ISR withholding at your marginal tax rate.

Understanding the Variables

The primary inputs to the calculator are your gross Aguinaldo amount, your regular monthly salary, and your payroll frequency. The gross Aguinaldo is the total bonus you are legally entitled to receive, typically 15 days of salary but can be higher per company policy or collective bargaining agreement. Your monthly salary is your base pay before any deductions such as IMSS, INFONAVIT, or voluntary savings. The payroll frequency (weekly, bi-weekly, or monthly) determines which tax table the calculator uses, as the tax brackets and rates differ slightly based on the pay period. The UMA value is an automatic variable that the calculator updates annually, so you never need to look it up manually.

Step-by-Step Calculation

The calculation proceeds through five distinct steps. First, the calculator determines the exempt portion of your Aguinaldo by multiplying 30 by the current daily UMA value. Second, it subtracts this exempt amount from your gross Aguinaldo to find the taxable Aguinaldo portion. Third, it calculates the ISR on your regular monthly salary alone using the appropriate tax table. Fourth, it calculates the ISR on the combined total of your monthly salary plus the taxable Aguinaldo. Fifth, it subtracts the ISR on salary alone from the ISR on the combined amount. The resulting figure is the exact ISR withholding that must be applied to your Aguinaldo payment. This method ensures that you are taxed only on the additional income at your highest marginal rate, which is fair and legally compliant.

Example Calculation

Let's walk through a realistic example to illustrate how the Mexico ISR Aguinaldo Calculator works in practice. This scenario involves a typical salaried employee in Mexico City earning a monthly gross salary of $25,000 MXN with a standard 15-day Aguinaldo. The UMA value used is the 2024 daily rate of $108.57 MXN.

Example Scenario: María works as a marketing coordinator in Guadalajara with a monthly gross salary of $25,000 MXN. She is paid monthly. Her daily salary is $25,000 ÷ 30 = $833.33 MXN. Her Aguinaldo is 15 days × $833.33 = $12,500 MXN gross. She wants to know her net Aguinaldo after ISR withholding.

First, calculate the exempt portion: 30 × $108.57 = $3,257.10 MXN. Second, find the taxable Aguinaldo: $12,500 − $3,257.10 = $9,242.90 MXN. Third, calculate the ISR on her regular monthly salary of $25,000 MXN. Using the 2024 monthly tax table, the ISR on $25,000 MXN is approximately $2,456.48 MXN (after applying the lower tax bracket credits). Fourth, calculate the ISR on the combined income of $25,000 + $9,242.90 = $34,242.90 MXN. The ISR on this amount is approximately $4,178.62 MXN. Fifth, subtract: $4,178.62 − $2,456.48 = $1,722.14 MXN. This is the ISR withholding on María's Aguinaldo. Her net Aguinaldo is $12,500 − $1,722.14 = $10,777.86 MXN.

In plain English, María will receive approximately $10,778 MXN from her $12,500 MXN Aguinaldo after the government withholds $1,722 MXN in income tax. The exempt portion of $3,257 MXN represents about 26% of her bonus that is completely tax-free, while the remaining 74% is taxed at her marginal rate of roughly 21.4%. This calculation demonstrates why higher-income employees often see a larger percentage of their Aguinaldo withheld — their marginal tax rate is higher.

Another Example

Consider a different scenario: Carlos is a factory worker earning a weekly salary of $2,800 MXN (approximately $12,133 MXN per month). His daily salary is $400 MXN ($2,800 ÷ 7 days). His Aguinaldo is 15 days × $400 = $6,000 MXN gross. The exempt portion remains $3,257.10 MXN. Taxable Aguinaldo = $6,000 − $3,257.10 = $2,742.90 MXN. ISR on his monthly salary of $12,133 MXN is approximately $537.25 MXN. ISR on combined income of $12,133 + $2,742.90 = $14,875.90 MXN is approximately $839.40 MXN. The ISR on his Aguinaldo is $839.40 − $537.25 = $302.15 MXN. Carlos's net Aguinaldo is $6,000 − $302.15 = $5,697.85 MXN. This example shows that lower-income workers benefit more from the exemption, as a larger percentage of their bonus remains tax-free.

Benefits of Using Mexico Isr Aguinaldo Calculator

Using a dedicated Mexico ISR Aguinaldo Calculator offers substantial advantages over manual calculations or generic tax tools. The specific methodology required for Aguinaldo tax withholding is different from regular salary ISR, and errors can be costly. This free tool provides clarity, accuracy, and peace of mind during the busy year-end season. Here are the key benefits that make this calculator indispensable for both employers and employees.

  • Absolute Accuracy with Current Tax Tables: The calculator is programmed with the official SAT tax tables for the current fiscal year, including all bracket adjustments, tariffa mensual (monthly rates), and the correct UMA value. Manual calculations using outdated tables or incorrect conversion factors are the leading cause of payroll errors. This tool eliminates that risk entirely by automatically applying the most recent government data, ensuring your ISR withholding is exactly what SAT expects.
  • Time Savings for Payroll Professionals: For HR managers and accountants processing dozens or hundreds of Aguinaldos in December, manual calculation for each employee is impractical and error-prone. This calculator delivers instant results for any salary level, allowing you to batch-process calculations quickly. The step-by-step breakdown also serves as documentation for your payroll records, which is invaluable during an SAT audit or employee dispute.
  • Transparency and Employee Trust: When employees receive their Aguinaldo, they often question why their net bonus is lower than expected. By using this calculator, employers can provide a clear, itemized explanation of the ISR withholding. Employees can also use the tool independently to verify their payment, building trust and reducing year-end complaints. The detailed breakdown shows exactly how the exempt portion and marginal tax rate were applied.
  • Correct Handling of the Exempt Portion: Many people incorrectly assume that the entire Aguinaldo is tax-free or that only a small portion is exempt. The legal exemption is specifically 30 days of the daily UMA, not 30 days of the employee's salary. This calculator automatically applies the correct UMA-based exemption, preventing the common mistake of over- or under-withholding. For 2024, this means the first $3,257.10 MXN of any Aguinaldo is tax-free, regardless of the employee's salary level.
  • No Data Storage or Privacy Concerns: Unlike many online tools that require creating an account or storing your financial data, this calculator operates entirely in your browser. No salary information, Aguinaldo amounts, or personal data is sent to any server or saved in any database. You can use it as many times as needed without any privacy risk, making it ideal for sensitive payroll information.

Tips and Tricks for Best Results

To get the most accurate and useful results from the Mexico ISR Aguinaldo Calculator, follow these expert tips and avoid common pitfalls. While the tool is designed to be intuitive, understanding the nuances of Mexican tax law will help you interpret the results correctly and ensure full compliance with SAT regulations.

Pro Tips

  • Always use your exact daily salary based on your contract, not an average or estimated figure. The daily salary is calculated by dividing your monthly salary by 30 (the standard convention for Aguinaldo calculations in Mexico), regardless of how many actual days are in the month. Using an incorrect daily salary will result in an incorrect gross Aguinaldo amount.
  • If your employer provides an Aguinaldo greater than 15 days (common in many industries and union contracts), enter the full gross amount, not just the legal minimum. The calculator handles any amount correctly, and the exemption applies to the same 30 UMA days regardless of the total bonus size.
  • For employees with variable income such as commissions or bonuses, use your average monthly salary for the last three months as a reasonable estimate. The calculator's results will be close to the actual withholding, though the precise amount may vary slightly depending on your exact December earnings.
  • Run the calculation before December 1st to plan your year-end budget. Knowing your net Aguinaldo in advance allows you to allocate funds for holiday expenses, savings, or debt repayment without surprises. Many employees are shocked when they see the ISR deduction, but advance planning eliminates this stress.
  • If you are an employer, use the calculator to test different scenarios for employees with different salary levels and payroll frequencies. This helps you budget for total payroll costs and ensures you have sufficient funds to cover both the gross Aguinaldo and the ISR remittance to SAT, which must be deposited by January 17th of the following year.

Common Mistakes to Avoid