Quick Answer

To withhold ISR or VAT when paying fees or rent, first identify the payer, recipient, tax regime, and concept. Then determine the applicable base and rate, deduct the withholding, pay the net amount, remit the tax, and keep the CFDI, calculation, and receipts.

Before paying fees or rent, identify the parties, concept, base, and obligations to correctly calculate and remit withheld ISR and VAT.

Confirm Current Rates

This guide organizes the process; the final calculation must be validated against the law, tax regime, and actual payment characteristics.

Decision Matrix

QuestionWhat it definesDocument
Who pays?Possible withholding obligationTax certificate
Who receives?Regime and treatmentRFC and contract
What is paid?Base and ruleContract and CFDI
When?Remittance periodBank and accounting entry

Example: same person, two different concepts

A company pays a natural person fees for consulting and also rent for an office. Although the recipient is the same, contracts, CFDIs, bases, withholdings, and payments are kept separate. A single entry or copied rate can mix different obligations and cause inconsistent certificates.

The withholding is determined by the nature of the payment and the parties involved, not by copying the percentage from the previous invoice.

— Fintax

How to think about a withholding

Withholdings are taxes that the payer deducts and remits on behalf of the recipient. For fees, rent, and other payments, the result depends on who pays, who receives, and the actual economic concept.

The invoice helps document the transaction, but the calculation must be validated against the contract and current rules. If the CFDI does not match the payment or withholding, correct it before closing the period.

Errors that cause discrepancies

  • Applying a rate out of habit.
  • Not separating fees, rent, and other concepts.
  • Paying the net amount without recording the withheld liability.
  • Declaring an amount different from the CFDI and working papers.

Sequence from contract to receipt

  1. Read contract and CFDI.
  2. Classify parties and regime.
  3. Calculate base, tax, and withholding.
  4. Pay net and record liability.
  5. Remit and reconcile with receipts.

Control before paying

  • Identify payer and recipient.
  • Classify the actual payment concept.
  • Confirm applicable regime and treatment.
  • Review base, rate, and CFDI.
  • Remit, declare, and keep certificate or receipt.

Frequently Asked Questions

Does every invoice from a natural person require withholding?

No. It depends on the concept, regime, payer, and recipient; review the specific transaction.

Is the withholding calculated on the total amount?

First identify the base and taxes shown; do not use the total without separating concepts.

What does the payer keep?

Contract, CFDI, calculation, payment to supplier, declaration, payment slip, and receipt.

Sources and readings to continue

Consult official sources: ISR Law, VAT Law, SAT declaration service.

To complete the process within Fintax, review: CFDI guide, declarations and receipts, annual closing for companies.

What to do now

Turn this review into a file with responsible person, date, source, and evidence. If there is a material difference, an overdue obligation, or a decision that changes the calculation, validate the case with your accounting responsible before filing, canceling, or paying.