Tell consumers the full price of an international payment: the estimated* total cost of any fees and the exchange rate mark-up (the difference between the exchange rate offered to the customer and an independent mid-market rate like the one you see on Google). This needs to be communicated to consumers clearly as a total cost of fees (e.g. £3.14 or whatever the currency used) and may additionally be expressed as a percentage. 

Governments around the world are starting to take notice of the problem of hidden fees. But we’re not waiting for government action. We want bank and remittance providers to commit to showing the true cost of an international transfer, wherever consumers are transferring money, whether they are using the service online or offline, whether they are a small business or a consumer: exchange rate mark-ups and all!

*only estimated as the total cost may vary if the exchange rate is not guaranteed to the customer through a rate 'lock' or 'guarantee'