Mercado Pago and Mercado Libre automatically deduct gross receipts tax (Ingresos Brutos) on each sale, but not always: it depends on your tax status in the province you're selling to.
The rule
- If your tax address is in the same province as the buyer, IIBB isn't withheld — as long as you're registered in that province. In that case you declare and pay it yourself directly.
- If you sell to other provinces where you're not registered, it's withheld automatically on every sale.
That's why two sales of the same product can have different withholdings: what changes is the destination province.
Where to check how much was withheld
Inside Mercado Pago, in the left sidebar, go to Billing → Taxes. Choose last month as the period and look for the IIBB and SIRTAC withholdings.
Divide that total by your revenue for the same period and you get your average percentage, which is usually between 3% and 5%.
Use that percentage as a reference to enter the store's tax in Escalafy, so it's reflected in your real profitability. If you use Pago Nube on Tiendanube, you'll find the same reports inside the Pago Nube platform.
Since it's an average, an individual sale can come out a bit above or below depending on the province. Over a full period the result is very accurate.