UNDERSTAND YOUR PAYROLL

Why did my ISR change?

Review a month's payments and the withholding on your payslips. No signup; amounts stay in this browser.

For ordinary payroll wages. The ISR reference does not validate your payslip or calculate IMSS contributions. ISSSTE, self-employment, termination and special adjustments are not modeled.

1. Enter your payments

The example shows a difference; it does not establish that the deductions are correct.

Payment month

Which income amount do you have?

If tax treatment is unknown, review actual deductions without a theoretical estimate. An off-payslip payment is not automatically tax-exempt.

Generate dates and copy amounts

Replaces the list with dates starting from your chosen first date and copies the first row's amounts. Adjust every actual payment.

First payment date

Payments are grouped by payment date. If the covered period crosses months, confirm its treatment with payroll. No 14-day withholding tariff is calculated.

Payment 1

Payment date 1

Gross / recorded income 1

Actual ISR withheld 1

Known exempt portion 1

For an optional monthly referenceI included all payments in this month from one employer.Ordinary wages only: no termination, special gratuities or local wage tax.I received only minimum wage (special case; no reference).

Complete amounts from 0 to 10,000,000 with up to two decimals. Enter 0 if no ISR was withheld.

Do not upload payslips, tax IDs or personal details. Reloading clears this list.

2. Understand the difference

Enter payments and select Review my payments. After editing, review again before exporting.

Sources and method

Monthly reference for a complete month of ordinary wages from one employer. It does not reproduce your employer's method. Excludes IMSS, local tax, other deductions and annual settlement. A difference does not determine an incorrect charge or a refund.

ISR: fixed quota + excess × monthly bracket rate. Subsidy: monthly UMA × 15.02%; January uses 2025 UMA × 15.59%, bounded by ISR and monthly eligibility. Same-date payments are grouped to analyze the last date.