You turn on interest-free installments because they "lift conversion." Sales go up. You feel good. But nobody told you that you're the one paying for that "interest-free." And if you didn't run the numbers, you're selling at a loss.
How interest-free installments work: what Mercado Pago doesn't explain on the front page
When a customer buys in 12 "interest-free" installments, someone has to absorb that financing cost. That someone is you, the seller.
Mercado Pago charges you a cost for offering interest-free installments, on top of the processing fee. These are the official costs in Argentina, in effect since February 10, 2026:
| Interest-free installments | Cost to the seller (+ VAT) |
|---|---|
| 2 installments | 7.79% |
| 3 installments | 10.49% |
| 6 installments | 18.69% |
| 9 installments | 26.49% |
| 12 installments | 32.29% |
| 18 installments | 41.59% |
On top of that comes the processing fee, which depends on when you withdraw the money: 6.29% instantly, 4.39% at 10 days, 3.39% at 18 days and 1.49% at 35 days, also + VAT (rates for CABA, the city of Buenos Aires; in other provinces they vary by a few tenths of a point). Sources: Mercado Pago's pages on interest-free installments and Checkout fees.
The result: if your gross margin is 45% and you sell in 6 installments with an 18-day payout, installments plus processing fee take 22 points before VAT. You have less than 23 points left to pay for shipping, advertising and returns. On 12 installments, the installment cost alone is already bigger than most stores' margin. How much ROAS you need in each case is worked out in Break-Even ROAS with installments.
The problem isn't offering installments. The problem is not knowing what each sale costs you depending on the payment method. A cash sale and a sale in 12 interest-free installments are not the same sale. They have completely different margins.
The three most common mistakes with interest-free installments
- Turning on installments without calculating the minimum margin required: if your margin doesn't cover the installment cost, every installment sale is a loss
- Not setting a minimum order amount for installments: low tickets on installments wreck your margin because the fixed processing cost weighs more
- Not knowing what percentage of your sales are on installments: if 60% of your sales are on installments and you don't account for it, your P&L is wrong from the ground up
How to calculate the real impact on your margin
For each product or category, you need to know:
- Your gross margin per product (sale price minus product cost)
- What percentage of that product's sales go on installments, and how many installments
- The exact Mercado Pago fee for each installment combination
- The shipping and logistics cost
- The product's return or claim rate
This is what no Excel spreadsheet can do automatically — because the data lives in four different places and changes every day.
What Escalafy calculates for you, in real time
Escalafy integrates directly with Mercado Pago and Tiendanube (or Shopify), and for every sale it records the exact payment method, the installments and the fee applied.
- Real margin per sale: including the Mercado Pago fee for the installments used, not an average estimate
- Average margin by payment method: you see whether installment sales are profitable or not
- Sales breakdown by payment method: you know what real share of your business goes through each option
- Cash flow forecast by payment method: installments settle differently, and Escalafy tells you when every peso comes in
Interest-free installments can be a competitive edge — if you manage them well
We're not saying turn off installments. We're saying use them intelligently.
With real visibility, you can:
- Set prices that already account for the installment cost on high-ticket products
- Limit installments to minimum amounts where the margin can handle it
- Offer a discount for paying in full without losing margin
- Know exactly what payment mix you need to be profitable this month
Interest-free installments are a tool. Like any tool, they can build or destroy depending on whether you know what you're doing.
Keep reading
How to calculate a product's selling price (without losing money on every sale)
Read E-commerce FinanceHow to calculate a product's profit margin (and why yours is half what you think)
Read E-commerce FinanceMercado Libre Full: what it costs, how it works and when it pays off (2026)
ReadWhat Escalafy does for your store
Connect your channels and see the truth behind your numbers. No Excel, in real time.