Learn · Foreign exchange
What is the interbank exchange rate, and why can quotes differ?
Learn what the interbank or mid-market exchange rate means, why customer quotes differ, and how to calculate the effective FX spread with an example.
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In short
What is the interbank exchange rate?
In everyday comparisons, “interbank” usually means a wholesale market reference near the midpoint between executable buy and sell quotes, also called the mid-market rate. It is a benchmark, not a promise that a business can transact any amount at that exact price. Your actual rate may include a spread, while a provider using the midpoint may charge an explicit fee instead.
Mid-market, reference, and customer rates
Three rates that answer different questions
| Feature | Mid-marketQuote midpoint | Published referenceInformation benchmark | Customer rateYour conversion quote |
|---|---|---|---|
| How formed | Midpoint of buy and sell quotes | Central-bank methodology, time, and source | Provider pricing for your transaction |
| Main use | Market comparison | Accounting, statistics, analysis, reference | Amount you can accept and execute |
| What can change it | Market prices and timestamp | Publication method and observation window | Amount, pair, funding, timing, risk, and markup |
| Executable? | Not necessarily | Usually explicitly not | Only within quote terms and validity |
Xe defines mid-market as the halfway point between buy and sell prices. The Bank of Canada publishes indicative averages from aggregated financial-institution quotes and warns that they may not reflect rates at which transactions could occur.
“The rate on Google” is often a data-vendor or central-bank reference, not an offer addressed to your company. The ECB says its euro reference rates are averages of buying and selling rates, intended for information, and not necessarily rates at which actual transactions occurred. A fair comparison names the reference, observation time, quotation direction, and amount.
Even reference sources differ. The Bank of Canada collects indicative mid-market quotes each minute during its stated business-day window, removes the highest and lowest 2.5% of observations, and averages the remainder. The ECB uses its own daily concertation procedure. Two trustworthy published rates can therefore differ without either being a customer quote.
Why your business quote differs
| Component | Where it appears | How to test it |
|---|---|---|
| FX markup | Customer rate differs from reference | Calculate rate disadvantage at the same timestamp |
| Conversion fee | Separate fixed or percentage line | Add it to the all-in cost |
| Funding fee | Card, bank, or method charge | Price each available funding method |
| Transfer fee | Fixed or corridor fee | Include even if no currency converts |
| Intermediary or recipient charge | Deducted in the payment chain | Confirm charge option and recipient net amount |
| Guarantee or timing condition | Quote expiry or funding deadline | Compare quotes that can actually be funded |
The UK FCA identifies rate markups, fixed and variable transaction fees, and possible intermediary or recipient-bank fees as parts of international-payment cost disclosure. Wise states that its fee varies with amount, payment method, and currency pair while it uses the mid-market rate.
How to calculate the effective FX spread
Keep the quote direction consistent. This method assumes the provider and reference both show destination currency per one unit of source currency.
Capture a reference rate
Record the source, timestamp, pair, and direction. Do not compare a provider’s live rate with yesterday’s central-bank reference in a moving market.
Capture the executable quote
Record source amount, customer rate, explicit fees, funding method, validity, destination amount, and whether third-party deductions can occur.
Calculate reference countervalue
Multiply the source amount by the reference rate. This is a comparison value, not a claim that the transaction was available at that price.
Calculate rate-only disadvantage
Subtract the quoted destination amount before explicit fees from the reference countervalue. Divide by the reference countervalue to express the difference as a percentage.
Calculate all-in disadvantage
Convert or allocate explicit fees into the same comparison currency, add them to the rate disadvantage, and include known recipient deductions.
| Line | Calculation | Result |
|---|---|---|
| ECB reference, 27 July 2026 | EUR 1 × USD 1.1389 | 1.1389 USD/EUR |
| Reference countervalue | EUR 100,000 × 1.1389 | $113,890 |
| Hypothetical provider rate | EUR 100,000 × 1.1104 | $111,040 |
| Rate-only disadvantage | $113,890 − $111,040 | $2,850 |
| Effective rate spread | $2,850 ÷ $113,890 | 2.50% |
| Plus hypothetical explicit fee | $2,850 + $200 | $3,050, or 2.68% |
The ECB observation is factual and informational only. The 1.1104 provider rate and $200 fee are invented solely to demonstrate arithmetic, not attributed to any provider. Percentages are rounded.
The example does not say the provider “charged 2.50%” as a disclosed fee. It says the destination amount is 2.50% below the ECB reference countervalue because of the rate difference. Adding the hypothetical $200 fee raises the all-in difference to 2.68%. This distinction keeps a calculated comparison separate from the provider’s contractual fee labels.
How to compare FX providers defensively
- Request quotes for the same source amount, pair, direction, beneficiary country, speed, and funding method within a short time window.
- Record the independent reference rate at each quote timestamp rather than comparing every quote with one stale screenshot.
- Compare the guaranteed recipient amount, not only the headline rate or transfer fee.
- Ask whether intermediary, correspondent, recipient-bank, tax, or lifting deductions can reduce delivery.
- Check quote expiry, funding deadline, refund rule, cancellation terms, and the rate used if funds arrive late.
- For recurring volume, compare actual realized rates and fees from statements with the approved quote and invoice.
- Separate service value such as speed, controls, support, and reconciliation data from the pure conversion cost.
A quote also has a time dimension. Wise says the mid-market rate moves continuously and that some currency quotes can be guaranteed only if the provider receives the full required amount within the stated window. For any provider, record when the quote was created, when it expires, which amount must arrive, and what happens if funding is late. Otherwise an apparent rate comparison may compare one executable offer with another offer that was never fundable on the same terms.
Interbank-rate questions
Is the interbank rate the same as the mid-market rate?
Can a business actually get the mid-market rate?
Why is the ECB rate different from my bank quote?
What is an FX markup?
How do I compare rates quoted in opposite directions?
Is a zero-transfer-fee quote cheaper?
Should accounting use the customer rate or a central-bank rate?
Sources
External links open in a new tab.
- What is the mid-market rate? — Xe
- What is the mid-market exchange rate? — Wise
- Background information on foreign exchange rates — Bank of Canada
- What is the role of exchange rates? — European Central Bank
- Euro foreign exchange reference rates — European Central Bank
- International payment pricing transparency — Financial Conduct Authority
- Send money abroad with more confidence — Consumer Financial Protection Bureau
- Fees for sending money — Wise
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Glide Research
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