Currency converters disagree because each strikes its rate from a different source at a different moment. Central bank reference rates are set on a schedule and published for information only, and the European Central Bank strongly discourages using them for transaction purposes. A converter shows a reference rate, not a dealing rate, so the number a customer is actually offered differs again by the margin the provider applies.
Two converters showing different numbers for the same pair are usually both correct. They are answering a slightly different question, and the difference between them is smaller than the difference between either of them and the rate a customer is actually offered.
Key Takeaways
- A converter shows a reference rate, which is a scheduled observation rather than an offer.
- European Central Bank reference rates come from a daily procedure around 14:10 Central European Time, published around 16:00.
- The ECB publishes them "for information purposes only" and says using them for transactions is "strongly discouraged".
- Australia has floated its currency since 1983, so there is no official rate to look up, only observations.
- The gap between a reference rate and a quote is the margin, and the ACCC warns a "fee free" service is not necessarily the cheapest.
A reference rate is struck, not streamed
The first reason two converters differ is that a reference rate is a snapshot taken deliberately, at a scheduled time, so that every user of it is looking at the same instant.
The European Central Bank's euro foreign exchange reference rates are based on a daily concertation procedure between central banks across Europe, which normally takes place around 14:10 Central European Time. The rates are usually updated at around 16:00 the same day, on every working day except days when the payment system is closed.
Two converters drawing on different sources, or refreshing at different points, are therefore reporting two different instants. Over a quiet hour that difference is invisible. Over an hour when a currency is moving, it is not.
What the publisher says the rate is for
The institutions that publish these rates are unusually direct about their limits, and the disclaimer is worth reading in full because it settles most arguments about which converter is right.
The ECB's note reads: "The reference rates are published for information purposes only. Using the rates for transaction purposes is strongly discouraged."
That is the publisher of the number saying it is not a price. A reference rate records where the market was at one moment; it commits nobody to dealing there. Asking which converter has the "real" rate is therefore the wrong question. None of them do, because a reference rate is not the kind of thing that has a real version.
A published rate has an age
The scheduling has a consequence that catches Australian readers specifically, because of where Australia sits relative to European market hours.
Central European afternoon is the middle of the night in Australia. A rate read over an Australian weekend was struck on the last European working day, and markets have been closed in between. An unmoving figure means nothing has been trading, not that the currency is holding steady.
So a converter checked on a Sunday afternoon in Sydney and one checked on Monday morning can differ by the whole weekend's worth of news, with neither having done anything wrong.
There is no official Australian dollar rate
Australia moved to a floating exchange rate in 1983. As the Reserve Bank explains, in "a floating regime, exchange rates are generally determined by the market forces of supply and demand for foreign exchange".
Nobody sets the number. Day-to-day movements can reflect speculation or news, while shifts over longer periods reflect interest rate differentials, international competitiveness and the relative economic outlook. Because the value is discovered in trading rather than announced, there is nothing to look up except observations of where trading occurred, and different observers observe different moments.
A related trap is reading one pair as though it described the currency, since a bilateral rate has two moving sides. The trade-weighted index is the standard check against that, and what drives the AUD/USD rate sets out how to use it.
Mid versus retail, which is a larger gap than any of this
Everything above concerns differences of a fraction of a per cent between one published observation and another. None of it is the number that decides what a transfer costs.
A reference rate is a wholesale midpoint. What a retail customer is offered sits some distance away from it, and that distance is the exchange rate margin, which is typically far larger than the gap between two converters. It is also invisible in a fee comparison: the ACCC warns that "a service advertised as 'fee free' does not mean it will be the cheapest option", and advises consumers to "consider all parts of the price when comparing services and suppliers", including "the retail exchange rate and any fees".
How a margin trades off against a flat fee, and why the answer changes with the size of the transfer, is set out in understanding transfer fees. The practical upshot for reading a converter is narrower: the figure on screen is a yardstick for measuring quotes, and the quote that settles a comparison is the amount the recipient actually receives.
Where to look next
The mid-market concept has its own definition at mid-market rate, alongside interbank rate, spot rate and trade-weighted index. How margins and flat fees trade off against each other by transfer size is covered in the guide to transfer fees, and the methodology page sets out how the rates on this site are struck.
Sources
- European Central Bank, Euro foreign exchange reference rates - the concertation procedure, publication schedule and the information-only disclaimer
- Reserve Bank of Australia, Exchange Rates and their Measurement - the float since 1983, and the trade-weighted index
- ACCC, Foreign currency and money exchange - comparing the full price, and fee free claims
Not financial advice, and not a recommendation of any product or institution. Reviewed by the Tradergy editorial team, September 2026.
Common questions
Why do two websites show different rates for the same currency pair?
Because each strikes its figure at a different moment and may draw on a different source. Over a period when a currency is moving, seconds are enough to produce a visible difference, and neither figure is wrong.
Is the rate a converter shows the rate I will get?
No. A converter shows a reference rate, which is a published observation of where the market sat. The European Central Bank publishes its reference rates "for information purposes only" and says that "using the rates for transaction purposes is strongly discouraged".
When are central bank reference rates set?
On a schedule. The European Central Bank's euro reference rates are based on a daily concertation procedure between central banks that normally takes place around 14:10 Central European Time, and the rates are usually published around 16:00 the same day on working days.
Why does a rate not move over the weekend?
Because foreign exchange trading is thin or closed across the weekend and central banks do not publish reference rates on non-working days. The last struck value carries over, so an unchanged figure means nothing has traded rather than that the currency is stable.
Is the mid-market rate the same as the interbank rate?
The terms are used loosely as synonyms. Both describe the midpoint of the wholesale market rather than a retail price, and neither is a rate offered to a consumer.