What the mid-market rate actually is, why your bank's rate is worse, and a worked example of a £100 transfer through three providers.
Open any fintech ad and you'll see the phrase "mid-market rate". Wise built a brand on it. Revolut put it on the homepage. Your bank almost certainly didn't mention it because the answer is embarrassing.
Here's what it actually is, why it matters when your group is splitting expenses across currencies, and a worked £100 transfer through three providers so you can see the real cost.
The mid-market rate is the midpoint between the global wholesale buy and sell prices for two currencies - the closest thing to a "real" exchange rate. Banks and most card networks add a 2-4% spread on top, which is the fee. Wise / Revolut / a few neobanks pass on the mid-market rate and charge a small explicit fee instead.
Currencies don't have a single price. They have two prices at any given moment:
The difference between bid and ask is the wholesale spread - usually a fraction of a penny. The mid-market rate is just the midpoint: (1.1782 + 1.1786) / 2 = 1.1784.
It's the rate banks and forex desks see when they trade with each other in £100 million blocks. It's the rate Reuters and Bloomberg quote. It's the rate Google and XE.com show you when you search "GBP to EUR".
Because your bank doesn't pass on the mid-market rate. They give you their rate, which builds in a spread - a margin between what they pay wholesale and what they charge you.
That spread is typically 2-4% for high-street banks, occasionally higher for low-volume currencies, occasionally lower for high-balance customers. It's often advertised as "no fees!" - which is technically true. The fee is hidden in the rate.
Worked example. Mid-market is 1.1784 GBP/EUR. The bank quotes you 1.1426. You convert £1,000.
Three percent is a real number. On a £3,000 group holiday paid in EUR, that's €106 of friction nobody costed in.
Wise, Revolut, and a small group of others pass on the mid-market rate (or something within fractions of a percent of it) and charge a small, explicit fee.
Worked example. Same £1,000 conversion, through Wise.
Difference vs the bank: about €31 better off. Not life-changing on a £1,000 transfer, but the same percentage on a £30,000 house deposit transfer is the difference between a holiday and not.
Revolut is similar but plays games at the weekend - rates are slightly worse on Saturday and Sunday because the wholesale FX market is closed and Revolut takes a "weekend markup". Most other providers do something similar.
Most UK credit cards charge a "non-sterling transaction fee" of 2.75-3% on top of an already-marked-up rate. So when you tap a card in Lisbon, you're paying somewhere around 3.5-5% over the mid-market rate.
The exceptions:
Three reasons.
You and four friends are in Lisbon. You put €240 of dinner on your UK Halifax debit card. Your bank converts at their rate. You see £215 leave your account.
At mid-market, that €240 should have been £203.50. You paid £11.50 of hidden FX cost.
Now the group splits the expense five ways. You log €240 (the local-currency total) in the splitter. The app converts at mid-market and tells everyone they owe you £40.70.
That's correct as far as the group is concerned. But you're still £11.50 down because of your bank's spread. You absorbed the cost; the group didn't.
We have a longer piece on this in foreign card fees: how they distort group expense maths.
If your group is split across UK and EU members, settle in EUR if you can. The settlement involves one cross-border transfer per non-local member; doing each transfer in EUR (the local currency for the bills) avoids stacking FX spreads.
EvenRound auto-detects your country and sets the default currency. We covered the auto-detection in whose card pays for the Airbnb? And other tricky trip questions. Picking the wrong default means every expense is converted at entry, which compounds rounding error.
The rule of thumb: set the group currency to whatever currency most expenses will be paid in. For a UK group on a Lisbon trip, that's EUR.
Here's a real, recent £100 transfer from GBP to EUR, fees and rates measured to the cent.
On £100, the difference is about €3. On £1,000, €30. On £10,000, €300. The percentage is the same; the absolute number scales.
Two practical changes that have stuck:
First: when on a group trip abroad, the person fronting big-ticket items pays in local currency from a Wise card or equivalent. Skips the bank's spread entirely. The group's split maths matches the actual cash that left their account.
Second: when settling cross-border, route through the cheapest provider for the corridor. For GBP-EUR that's usually Wise. For GBP-USD it's sometimes a different answer (Revolut and Wise are close). For long-tail corridors (PHP, NGN, INR), Wise is usually still the cheapest, but worth checking.
On your next multi-currency trip, create a groupand set the default currency to wherever you're going. Each member enters expenses in whatever currency they paid in - the app converts to the group currency at mid-market for the running balance. Settle-up at the end is one transfer per person.
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