This story was purely on my own whim. Not paid. I took a Wise card and a NAB Visa debit card to Bali for ten days to see which one cost me less. The results were a little shocking.
I assumed the difference would be the exchange rate. It wasn’t. The rates were the same. Out by a cent or two on a coffee, nothing more. The difference showed up two days later, when the NAB fees started appearing in the app.
A gelato at Ettore in Pererenan. Fifty thousand rupiah, about four dollars. NAB converted it at $3.97. Wise converted it at $3.97. Then a separate line item appeared under the NAB transaction. International transaction fee: 14 cents.
| 50,000 IDR gelato | NAB | Wise |
|---|---|---|
| Converted cost | $3.97 | ~$3.97 |
| Fee | $0.14 | $0.01 |
| Paid | $4.11 | $3.98 |
Thirteen cents apart. Not worth changing banks over.
The reason the rates matched is that the fee isn’t in the rate. NAB converts at close to the market rate, then charges 3.5% as a separate transaction fee afterwards. Comparing exchange rates tells you nothing, because the exchange rate isn’t where the money goes.
Here’s Friday 14 August on the Wise app.
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| Friday 14 August | IDR | AUD |
|---|---|---|
| Optimist Bali | 424,800 | $33.86 |
| Surfer’s Bar | 39,200 | $3.12 |
| Circle K | 70,000 | $5.56 |
| Tonic Day Spa | 310,000 | $24.68 |
| Openhouse Cafe | 231,900 | $18.47 |
| House of Kairos | 173,250 | $13.80 |
| Circle K, again | 18,000 | $1.44 |
| Total | $100.93 |
Seven transactions, $100.93. Drinks at Optimist, a sunset beer at Surfer’s, a massage at Tonic, lunch at Openhouse, Circle K twice for ice creams.
Run that day through the NAB card at 3.5% and it costs another $3.53.
The percentage doesn’t change with the size of the purchase. A $30.02 lunch takes $1.05. A $19.85 lunch takes 69 cents. A $4.29 purchase takes 15 cents.
The structural difference is what gets charged for. NAB charges per transaction, so seven taps means seven fees. Wise charges per conversion. If you convert AUD to rupiah once and hold the balance, the seven taps that follow are spending money you’ve already converted. That’s why the gap opens up over a day rather than at any single purchase.
Wise charged one cent on $2.78 and one cent on $3.98. Wise does charge a fee. It uses the mid-market rate and adds a disclosed conversion cost. But one card was charging a percentage every time and the other was charging once.
Something that shows up on neither statement: terminals in Bali routinely offer to bill you in Australian dollars. That’s a second conversion at the merchant’s rate, applied before your bank gets involved, and the markup is invisible. Always pay in rupiah.
Across ten days, 6 to 15 August, the identifiable NAB international transaction fees came to $41.52. That’s $4.15 a day. It’s provisional, because some charges were still settling when I wrote this.
Cash is even worse.
Pull rupiah from an ATM on an Australian card and you can get three charges on one withdrawal: the conversion, your bank’s overseas ATM fee at $5, and whatever the local machine charges.
Those sit separately from the $41.52. The $5 is flat, so the smaller the withdrawal the worse the percentage. Two million rupiah taken out in four goes costs four times what it costs in one.
In Europe, a 3.5% fee on a €900 hotel bill is thirty-odd euros in one hit. Bali was seven or ten small transactions a day. By the end of a fortnight there are dozens of them on the statement.
Scale the same rate up and it looks like this.
| Trip | Card spend | Fee at 3.5% |
|---|---|---|
| One week, Bali | $1,050 | $36.75 |
| Two weeks, Bali | $2,100 | $73.50 |
| Two weeks, Europe | $2,800 | $98.00 |
| Three weeks, Europe | $5,250 | $183.75 |
Every thousand dollars you spend on a bank card overseas costs another thirty-five.
If your overseas spending is one or two large transactions, none of this matters much. Book the flights on the points card and take the points.
Everything else belongs on a travel card.
Wise, or any travel card that converts at the market rate for a low disclosed fee instead of clipping 3.5% off every tap. Loading it takes a minute, PayID transfers cost nothing to receive, and you can convert your rupiah before you go and spend a fixed balance rather than paying to convert fifteen times a day. Sending money to the people you’re travelling with is instant, which is more than my bank manages domestically.
None of what NAB charged me was hidden. It was itemised on every line of the statement, correctly labelled, exactly as disclosed. The fee structure works because a 14-cent charge on a gelato is small enough that nobody checks, and by the time you do you’re home and it’s ten days too late.
Next time you travel, make sure you ditch the bank card and opt for a low fee travel card like Wise.
