Avoid capital gains tax (ISR) when selling a house in Mexico (2026)

Can you avoid paying capital gains tax (ISR) when selling a house in Mexico? Yes. If the property was your primary residence, the gain is exempt from income tax up to 700,000 UDIS — about $6,180,000 MXN in 2026 (approximately $310,000 USD at the estimated exchange rate) — and you can use the exemption once every three years. This guide covers the exact requirements, the cap updated to 2026, and the part almost no one explains well: what happens when your property is worth more than the limit.

This guide is informational and is not tax advice. The ISR is calculated and withheld by the notary at closing; confirm your specific case with your accountant and the SAT (Mexican tax authority).

What is ISR on the sale of a house, and why is it charged?

In a real estate sale, ISR (Impuesto Sobre la Renta — Mexico's income/capital gains tax) is not charged on the sale price but on the gain: the difference between what you paid for the property (plus improvements and deductible costs, adjusted for inflation) and what you receive when you sell. It is essentially a tax on the appreciation you generated.

The law (Article 93, section XIX of the Income Tax Law) provides an exemption for the taxpayer's primary residence. The goal is to avoid taxing the sale of the family home — but the benefit comes with rules, a frequency limit, and a cap that is updated each year with the UDI.

How to claim the exemption: the 3 key requirements

For the sale to be exempt you must meet all three conditions at once:

1. It must be your primary residence. The property must have been your home, and you must be able to prove it with documents in your name showing the property's address.
2. The gain must not exceed 700,000 UDIS (~$6.18M MXN in 2026). If it does, only the excess is taxed — you don't lose the entire exemption.
3. You must not have exempted another home in the last 3 years. The benefit is once every three years per taxpayer.

The notary validates all three before signing. If one is not met, they calculate and withhold the corresponding ISR.

How much is the exemption limit in 2026?

The cap is 700,000 UDIS (Investment Units). Because the UDI rises with inflation, the peso amount changes every year. With the UDI value in June 2026 (around $8.84 MXN, or about $0.44 USD), the math is:

Watch out: many articles still cite ~$4.6M or ~$5M MXN because they use old UDI values (2023-2024). The figure for 2026 is close to $6.18M MXN. Verify the exact UDI value on your closing date in the Diario Oficial de la Federación (Banxico publishes it twice a month).

What if your property is worth more than the limit? (high value)

This is the point almost no one explains well — and the one that matters most if you're selling a luxury property. You don't lose the exemption entirely when you go over the cap: the gain is exempt up to 700,000 UDIS and only the excess is taxed.

Illustrative example of a high-value residence:

Instead of paying ISR on the full $8M gain, you pay only on ~$1.82M. That's why, on large deals, the difference between maximizing deductions (inflation-adjusted cost, invoiced improvements, commissions, notary and acquisition tax) and not doing so can be hundreds of thousands of pesos. It's a technical calculation the notary performs; keep your documentation organized and, on multi-million-peso properties, review the scenario with an accountant before signing.

Documents to prove it was your primary residence

The notary needs proof that you lived there. The documents must be in your name (or your spouse, parents or children) and show the same address as the property you're selling:

• Valid official ID (INE or passport)
• Electricity, water, property-tax or landline phone bills
• Bank or store-account statements
• SAT Tax Status Certificate (Constancia de Situación Fiscal)

Keep bills with some history: they help support that the property was your residence. If the utilities aren't in your name, talk to the notary before selling to fix it in time.

How many times can you use it? The 3-year rule

The primary-residence exemption applies once every three years (the law reduced it from five to three years in 2016). If you sold and exempted another primary residence within the prior three years, this sale will be taxed. The notary checks the SAT system to see whether you already used the benefit, so it's not something you can "skip."

Step by step to claim the exemption at the notary

1. Gather the documents that prove the primary residence (list above).
2. Choose a notary and give them the documentation before signing the deed.
3. The notary verifies the address, the transaction value and the 3-year rule.
4. If the full exemption applies, no ISR is withheld. If you exceed the cap, ISR is calculated only on the excess.
5. The notary remits the tax to the SAT as a provisional payment and reflects it in the deed.

ISR exemption for foreigners: what changes?

Yes, a foreigner can claim the exemption — but what defines the benefit is not nationality, it's tax residency. There are two scenarios:

1. Foreigner who is a Mexican tax resident. If you live in Mexico (temporary or permanent resident) and the property is your primary residence, you exempt just like a national. The law even presumes —unless proven otherwise— that a foreigner whose home is in Mexico is a tax resident. In practice you need: to declare under oath, in the deed, that you are a resident for tax purposes; your RFC / tax status certificate (or the SAT tax-residency certificate); and the usual proof-of-address documents. The same caps apply: 700,000 UDIS (~$6.18M MXN) and once every 3 years.

2. Non-resident foreigner (you live abroad and use the property as a vacation home). You do not get the primary-residence exemption. You pay ISR on the sale: usually 25% of the total price, or 35% of the net gain (with deductions) if you appoint a legal representative in Mexico. In this case, maximizing deductions is key to lower the base.

A fine point worth confirming with your notary: the exemption covers the construction and the land up to three times the built area; land beyond that ratio is taxed. If you bought through a bank trust, also see our fideicomiso guide for foreigners and our complete guide to taxes when buying.

How to reduce ISR when the exemption does not apply

If the property wasn't your primary residence, you already used the exemption less than 3 years ago, or the excess is large, you can still lower the taxable base with legitimate deductions:

• Inflation-adjusted acquisition cost (by the INPC index) since purchase.
• Improvements and additions — only those backed by an invoice (CFDI).
• Commissions paid on the purchase and the sale.
• Notary fees, appraisals and acquisition tax (ISAI) you paid when buying.

That's why you should keep every invoice from the day you buy: they're what reduce your ISR the day you sell.

Common mistakes that cost you the exemption

• Utilities and bills in someone else's name (not the seller's or a direct relative's).
• Unknowingly selling a second exempted home within the prior 3 years.
• No invoices for improvements: without a CFDI, they aren't deductible.
• Assuming a non-tax-resident gets the same exemption as a resident.
• Setting the price or sale structure without reviewing the ISR before signing.

Conclusion

Selling your primary residence in Mexico can be fully ISR-free if you meet the requirements and the gain doesn't exceed the ~$6.18M MXN (700,000 UDIS) cap for 2026. And if your property is worth more, you don't pay on all of it — only on the excess, which can be reduced with good deductions. The difference between planning it and not, especially on high-value properties, is measured in hundreds of thousands of pesos. Arrive with your documents in order and review the calculation before signing.