Guide · Exchange rates explained
What is the mid-market rate?
The benchmark every exchange rate quote should be measured against, and the two-line calculation that turns a vague rate into a cost in pounds.
The short answer
The mid-market rate is the midpoint between the price at which the wholesale market will buy a currency and the price at which it will sell it. It is the rate you see on news sites and search engines, and nobody sells currency to the public at it. The gap between the mid-market rate and the rate you are quoted is the provider’s margin, and on a large transfer it is usually the biggest cost you pay.
By Charlie Hinwick, ACCA · Last updated 24 October 2026 · Sources listed at the foot of the page
How is the mid-market rate worked out?
At any moment, banks and dealers in the wholesale currency market quote two prices for a pair such as GBP/EUR: a bid (the price they will pay) and an ask (the price they will charge). The mid-market rate is the average of the two. It moves continuously while markets are open, so a mid-market rate is only meaningful with a time attached to it.
It is also called the interbank rate or the mid rate. The terms are used loosely, but the idea is the same: a reference price with no retail margin added.
How do you calculate the margin on an exchange rate?
You need two numbers taken at the same moment: the mid-market rate and the rate you have been quoted. Then:
- Margin (%) = (mid-market rate − your rate) ÷ mid-market rate × 100
- Cost in currency = amount × mid-market rate − amount × your rate
The example below converts £100,000 to euros at an illustrative mid-market rate of 1.1600. The two margins are illustrative too: they show the arithmetic, not any named provider’s pricing.
| Quote | Rate offered | Euros received | Cost versus mid-market |
|---|---|---|---|
| Mid-market reference | 1.1600 | €116,000 | — |
| Illustrative 0.5% margin | 1.1542 | €115,420 | €580 |
| Illustrative 3% margin | 1.1252 | €112,520 | €3,480 |
Notice that neither quote mentions a fee. Both could honestly be advertised as “no transfer fee”, yet one costs six times as much as the other. That is why we say on our methodology page that the margin is the one figure no UK currency broker publishes, and why we will not estimate one for them.
Can you get the mid-market rate?
Some providers convert at the mid-market rate and charge a separate, visible fee instead of a margin. That model makes the cost easy to see, and it is the pricing basis described in our Wise review. Most specialist brokers and banks instead build their charge into the rate itself. Neither model is automatically cheaper. The only fair comparison is the total amount the recipient receives for the same amount sent, at the same time.
Is the ECB reference rate the same as the mid-market rate?
No, and the European Central Bank says so itself. The ECB publishes euro reference rates at around 16:00 CET each working day, based on a daily concertation between central banks at around 14:10 CET. It states that the rates are published for information purposes only and strongly discourages using them for transactions. A reference rate is a snapshot from earlier in the day; the live mid-market rate keeps moving after it.
The practical point: when you check a quote, compare it with the live mid-market rate at the same minute, not with a published daily rate or a figure from the morning news.
How do you use the mid-market rate when comparing brokers?
- Ask each provider to quote the same amount, in the same direction, at the same time.
- Ask for the amount the recipient will receive after all charges, not just the rate.
- Note the live mid-market rate the moment each quote arrives.
- Work out each quote’s margin with the formula above, and add any fixed fee.
- Compare the totals. The cheapest quote is the one that delivers the most currency.
Our comparison table lists seven FCA-authorised brokers to quote from. For how the rate interacts with banks’ flat fees, see bank versus currency broker.
Frequently asked questions
Why can’t I buy currency at the rate I see on Google?
Because that figure is a mid-market rate with no margin. Any provider selling at it would earn nothing on the exchange, so it either adds a margin to the rate or charges a separate fee.
Is the interbank rate the same as the mid-market rate?
The terms are used interchangeably for a margin-free reference price. Strictly, banks dealing with each other still trade at bid and ask prices, and the mid-market rate is the midpoint between them.
What is a good margin on a currency transfer?
There is no published benchmark, because UK brokers and banks do not disclose margins. Calculate the margin on each live quote you receive and compare them directly; on a large sum, a few tenths of a per cent is worth hundreds or thousands of pounds.
Does the mid-market rate change at weekends?
The wholesale market largely closes at the weekend, so the rate shown is usually the last price from Friday. Providers that quote at weekends often widen their margin to cover the risk of a move before Monday.
Does a forward contract use the mid-market rate?
A forward contract is priced from the spot rate, adjusted for the interest-rate difference between the currencies, plus a margin. You can still measure that margin against the mid-market forward rate.
Sources
- European Central Bank: Euro foreign exchange reference rates (publication time, information-only status)
- ECB press release, 7 December 2015: changes to euro reference rates
- The Payment Services Regulations 2017
Related guides: sending a large sum abroad · all transfer guides by country
Put the margin test to work
Shortlist two or three FCA-authorised brokers, request quotes for the same amount, and let the arithmetic decide.
Last updated 24 October 2026 · Compiled and checked by Charlie Hinwick, ACCA. Nothing on this page is a personal recommendation or regulated financial guidance. All rates on this page are illustrative, not live quotes.