Exchange rates: Amazon and Nationwide

I closed my checking account with Nationwide^* when they stopped accepting foreign-currency check deposits but I still have a UK credit card open with them. Of my credit cards, that Nationwide card has the lowest credit limit so I use it for online purchases.

In ordering from Amazon US I have the choice of charging the card in USD or GBP. I noted what Amazon offered for their conversion and now find what I was actually charged for Nationwide's conversion. For an order of $71.44 Amazon offered 1 USD = 0.7792382758 GBP to charge me £55.67. Instead I charged the amount in USD to Nationwide who used U.S. DOLLA at 1.33010612 costing me only £53.71. Nationwide's conversion wins.

^*Nationwide is a large British building society unrelated to the American insurance company of the same name even though they are both mutually owned and have both claimed to be on my side.