As of May 2026, the IOF on international card purchases in Brazil is 3.5%, not 6.38%. That outdated number became folklore. Meanwhile, banks charge you a 4-6% spread on top of the wholesale dollar rate — a piece that doesn't even appear by name on your bill. This guide shows the real formula, compares eight cards and global accounts with the final effective exchange rate, and explains why a "no-IOF card" sometimes costs more than a regular one.
16 min read
Every time a Brazilian swipes a card abroad, they pay two tolls. The first has a name, a rate, and shows up on the bill: IOF, 3.5% in May 2026. The second has no name, isn't broken out, and is bigger than the first: the issuing bank's currency spread. It's a percentage the bank adds on top of the wholesale dollar rate before converting your purchase to reais. You never see this number. You only see the end result.
Most articles about IOF online still cite 6.38%. That number has been dead since 2022, when the Brazilian government progressively reduced the rate until consolidating at 3.5% for international credit card purchases. The 6.38% figure survives in outdated content, blog spreadsheets and collective memory. The upshot: millions of Brazilians believe they pay more tax than they do — and ignore the real toll, which is the spread.
This article unpacks the math calmly. Shows the formula. Shows it card by card. And shows how to measure your own card's spread in 30 seconds.
The wrong premise Google still repeats
TL;DRRun the search now. "IOF cartão internacional". The top results mix 6.38%, 5.38%, 4.38% and 3.5%. Each from a different year, each without a clear date. It's the legacy of a government that cut the rate in stages — January 2022 started at 6.38%, fell to 5.38% in 2023, then 4.38%, then 3.38%, and in 2026 settled at.
Run the search now. "IOF cartão internacional". The top results mix 6.38%, 5.38%, 4.38% and 3.5%. Each from a different year, each without a clear date. It's the legacy of a government that cut the rate in stages — January 2022 started at 6.38%, fell to 5.38% in 2023, then 4.38%, then 3.38%, and in 2026 settled at 3.5% after the final adjustment.
The consequence of this confusion: a Brazilian sees a USD 100 purchase turn into R$ 615 on the bill and thinks they paid R$ 38 in tax. They didn't. They paid R$ 18.50 in IOF and R$ 31 in bank spread. The tax is half what it seems. The rest is the invisible toll.
Anyone still quoting 6.38% is peddling stale information. And anyone attacking only the IOF is attacking the wrong villain.
The real formula (memorize this line)
TL;DREvery international card conversion follows the same formula: Effective rate per USD 1 = wholesale USD of the day × (1 + bank spread) × (1 + IOF) In May 2026, with a 3.5% IOF, the formula becomes: Effective rate = wholesale USD × (1 + spread) × 1.035 The wholesale USD is the interbank reference dollar (the.
Every international card conversion follows the same formula:
Effective rate per USD 1 = wholesale USD of the day × (1 + bank spread) × (1 + IOF)
In May 2026, with a 3.5% IOF, the formula becomes:
Effective rate = wholesale USD × (1 + spread) × 1.035
The wholesale USD is the interbank reference dollar (the number Google shows when you search "dollar today"). The spread is what the bank adds. The IOF is the federal tax. That's it.
Example with wholesale USD at R$ 5.40 (~USD 1) and a 6% bank spread:
- Effective rate = 5.40 × 1.06 × 1.035 = R$ 5.92 per dollar
Same example with a 1% spread (fintech):
- Effective rate = 5.40 × 1.01 × 1.035 = R$ 5.64 per dollar
A R$ 0.28 gap per dollar. On a USD 1,000 purchase, that's R$ 280 more or less. The card you pick defines this math. Not the IOF.
About the author
Curadoria Voyspark
2 years in the Voyspark editorial team
Time editorial da Voyspark — escritores, repórteres, fotógrafos e fixers em Lisboa, Tóquio, Nova York, Cidade do México e Marrakech. Coletivo. Sem voz corporativa. Cada peça com checagem cruzada por um editor regional e um chef ou curador local.
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