ACOS on Mercado Libre: what it is and how to tell if your campaigns are profitable

What is ACOS on Mercado Libre?

ACOS stands for Advertising Cost of Sales: your Product Ads spend as a percentage of the revenue attributed to those campaigns.

Mercado Libre uses ACOS as its main ad-efficiency metric. In ROAS terms, a 10% ACOS equals a 10x ROAS. A 20% ACOS equals a 5x ROAS. They're two ways of saying the same thing from different angles. In practice, many sellers in Argentina try to keep their campaigns' ACOS under 12-15% — without checking whether that percentage sits above or below their real margin.

Why isn't ACOS enough to know if you're profitable?

ACOS only measures advertising. It ignores everything else. And on Mercado Libre, "everything else" can be 20% to 40% of your sale price:

• Mercado Libre's sales fee: between 10% and 22% depending on category and the buyer's installments.
• Shipping or Full fulfillment cost: between 4% and 12% of the sale price depending on weight, size and destination.
• Cost of goods: the biggest number, and the one most often forgotten when looking at the ads dashboard.
• Taxes and withholdings: Mercado Libre withholds VAT and gross receipts tax (IIBB) rates that shrink the amount paid out to you.
• Returns: a percentage of your sales ends in a refund, with logistics costs you don't get back.

If your net margin before ads is 15% and your ACOS is 17%, you're losing money on every ad-driven sale — even if the dashboard shows the campaign "in the green." To understand how Mercado Libre deducts fees on each sale, we recommend the Mercado Libre fees in Escalafy page and the article on how much Mercado Libre Full costs and whether it's really worth it.

How do you calculate your break-even ACOS?

Break-even ACOS is the maximum ad spend percentage you can afford before that product starts losing you money:

If a product's net margin before ads is $18,000 on a $100,000 price, your break-even ACOS is 18%. Any ACOS above 18% on that SKU loses money. If you want an 8% net profit, ACOS can't go above 10%.

This calculation changes by SKU, by category and depending on the installments the buyer chooses. A sale in 12 interest-free installments can carry a total fee (base + financing) above 22%. That shrinks the margin available for advertising and, therefore, lowers your break-even ACOS.

Is selling on Mercado Libre profitable compared with your own store?

Many e-commerce businesses in Argentina run both Mercado Libre and their own store and look at average profitability. The average usually looks fine because the own store has a higher margin and offsets Mercado Libre's losses. But you're not scaling the profitable channel — you're hiding the problem in the channel that's bleeding.

In the article Mercado Libre vs your own store: which is more profitable we look at when to prioritize each channel. You can also see profitability per SKU with Escalafy's product profitability tool.

How Escalafy connects Mercado Libre ACOS to your real profit

Escalafy connects directly to your Mercado Libre account. For each order, it takes the sale price, the actual fees charged (including the financing charge for installments), the product cost you loaded and shipping. The result is net profit per SKU — in real time.

From that number you can work out your real break-even ACOS and compare it with the ACOS each campaign is paying. If ACOS is above break-even, the campaign is destroying margin. If it's below, it's generating real net profit. No Excel, no manual cross-referencing — the information is ready in the dashboard whenever you need it.

ACOS is the starting point. Net profit is the destination.

Optimizing ACOS is useful. But optimizing ACOS without knowing your net margin per SKU is like tuning the fuel economy of a car that doesn't know whether it's headed in the right direction.

The goal isn't the lowest possible ACOS — it's the ROAS that maximizes your real net profit. And to get to that number you need all of Mercado Libre's costs in the same place as your advertising data.