Foreign Exchange

How currency margins quietly cost you (and how to see them)

24 September 2026 · 5 min read

When you send money abroad, the exchange rate you are given is rarely the exchange rate that actually exists. Between the two sits a margin: a small percentage added to the "mid-market" rate that most people never notice, because it is folded into a single number. It looks like the price of the currency. It is really the price of the currency plus a fee.

The mid-market rate, and everything on top of it

The mid-market rate is the midpoint between what buyers and sellers are willing to trade a currency for at a given moment. It is the rate you see on Google or a financial news site. No retail customer gets it exactly, but it is the honest reference point. A provider's real cost to you is the gap between that mid-market rate and the rate they hand you.

High-street banks commonly add 2 to 3%. Card networks and consumer apps vary. The number is often invisible because there is no line item that says "FX margin" on your statement, only a converted total.

Why a small percentage is not a small number

A 2.5% margin on a £250,000 supplier payment is £6,250. Make that payment monthly and it is £75,000 a year, spent on nothing but the spread. For a business moving money across borders regularly, FX margin is frequently one of the largest costs nobody has on a budget line.

  • It scales with volume, so the more you trade, the more it takes.
  • It is charged every time, so it compounds across a year of payments.
  • It is opaque, so it is rarely negotiated or even measured.

How to see it in three steps

1. Find the mid-market rate for your pair at the moment you convert. 2. Divide the rate you were actually given by the mid-market rate. 3. The difference, as a percentage, is your margin. Do this once and the cost stops being invisible.

What a better rate looks like

Wholesale FX, the kind that flows through interbank and Tier 1 liquidity rather than a retail desk, is priced far tighter. Vault Money typically works to around 0.4%, roughly a sixth of a 2.5% bank margin, because we route client flow through a network of regulated counterparties instead of a single bank's retail pricing.

The point is not to trust a headline number, though. It is to measure your own. Put your real transfer size and currency pair into a calculator that shows the bank margin next to a tighter one, and you will see exactly what the spread is costing you.

See your own numbers

Our FX savings calculator compares a traditional bank margin with Vault Money on your transfer size and currency pair.

Open the FX calculator

This article is general information, not financial advice. Vault Money L.L.C-FZ introduces clients to a network of regulated and licensed counterparties and does not itself hold a banking licence or take title to client funds.

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