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The short answer
The FX margin is the difference between the exchange rate a provider gives you and the mid-market rate, the midpoint of wholesale buying and selling prices. It is a cost even when no fee is charged. You measure it by dividing the rate you are offered by the mid-market rate at the same moment.
When you send pounds to Nigeria, someone has to sell you naira. The price they charge for that is the exchange rate, and most providers set it a little below the wholesale price. That gap is the FX margin. It is often the largest cost on a transfer, and it is rarely shown as a separate line.
What the mid-market rate is
Currency dealers quote a price to buy and a price to sell. The mid-market rate sits halfway between them. It is the rate you see on public references such as Google, XE or Wise. Nobody retail can usually trade at exactly that rate; it is the benchmark you measure against.
Barclays, for example, says on its international payments page that its rate for a payment is a mid-market reference rate plus an FX margin, and that customers can ask for the margin by phone or in a branch. Wise states that it uses the mid-market rate and charges a separate, visible fee. These are two different pricing models, and both can be compared once you turn them into the same figure.
How to measure the margin
- Open a mid-market reference and note the GBP to NGN rate.
- At the same time, note the rate your app or bank offers.
- Divide the offered rate by the mid-market rate and subtract the result from 1. That is the margin as a percentage.
- Multiply the margin by the amount you are converting to get the cost in pounds.
A labelled example
Example only, with invented rates. The mid-market rate is ₦2,000 per £1 and your app offers ₦1,970. 1,970 ÷ 2,000 = 0.985, so the margin is 1.5%. On £500 that is £7.50; on £2,000 it is £30. If the same app also charges a £2 fee, your total cost on £500 is £9.50.
| Amount converted | Margin 0.5% | Margin 1.5% | Margin 3% |
|---|---|---|---|
| £100 | £0.50 | £1.50 | £3.00 |
| £500 | £2.50 | £7.50 | £15.00 |
| £2,000 | £10.00 | £30.00 | £60.00 |
Why the margin on naira can vary
- Market conditions. Wise notes it may not guarantee a rate in volatile markets, and that its rate hold runs 2 to 48 hours depending on the currency.
- Weekends. Wise says transfers set up at the weekend get the last available rate from Friday; other providers may widen margins when markets are shut.
- Promotions. Some first-transfer offers narrow the margin once; later transfers return to normal pricing.
- Nigerian market structure. Techeconomy reported in March 2026 that the CBN circular effective 1 May 2026 points money transfer operators to Bloomberg's BMATCH prices as the pricing reference for naira payouts. How each provider sets its own margin on top is its own decision.
Margins you cannot see
On bank SWIFT payments, intermediary banks may deduct charges and, if the payment is converted further along the chain, another conversion can happen. Barclays warns that intermediary banks may charge and reduce the amount received. If you send pounds to a Nigerian GBP domiciliary account, the conversion happens later, at your recipient's bank, at that bank's rate. See sending pounds to a domiciliary account.
Fee and margin together
A fee you can see and a margin you cannot see are both costs. The total cost of a transfer is the fee plus the margin on the amount converted. A provider with a £3 fee and a 0.5% margin costs £5.50 on £500 (example figures); one with no fee and a 1.5% margin costs £7.50 on the same amount. A provider with a £5 fee and a 0.2% margin costs £6. The cheapest structure depends on the amount, which is why small and large transfers can have different winners.
When comparing apps
- Enter the same pound amount in each app at the same time.
- Note the naira received after all fees.
- Divide naira received by pounds paid to get the effective rate.
- Compare effective rates with the mid-market rate to see the full cost in one number.
Questions worth asking a provider
- Is the rate shown the rate I will get, and for how long is it held?
- Is any fee charged on top, and does it depend on how I pay?
- Will my recipient's bank or any other bank deduct anything?
- Is the amount paid out in naira, and to which kind of account?
What to check first
- Compare the naira received, not the advertised rate alone.
- Check the rate is held while you pay.
- Recheck on each transfer; margins change.
For why banks often give fewer naira than apps, see banks versus apps.
Where Pryme fits
Pryme's Swap shows the rate first and the fee on its own line, and nothing converts until you approve, so you can see both parts of the cost before you commit. Your pounds stay in pounds in your multicurrency account until you choose.
Questions people ask
What is a good FX margin for pounds to naira?
There is no official benchmark. Measure each offer against the mid-market rate at the same moment and compare the naira received.
Is the FX margin a hidden fee?
It is a cost built into the rate. Some providers, such as Wise, show a separate fee and say they use the mid-market rate; others include their margin in the rate.
Can I ask my bank what margin it charges?
Barclays says customers can get their FX margin by calling or asking in a branch. Other banks publish their own terms.
Why does the rate change while I am paying?
Rates move with the market. Most providers hold a rate for a set period; Wise states 2 to 48 hours depending on currency.
Sources
- Barclays: International payments · accessed Oct 2026
- Wise: Send money to Nigeria · accessed Oct 2026
- Wise Help Centre: What's a guaranteed rate? · accessed Oct 2026
- Techeconomy: What the CBN naira-only remittance policy means (28 Mar 2026) · accessed Oct 2026
This article is general information, not financial, legal or tax advice. Products described are provided under the terms on this site and are subject to regulation and eligibility.