I would hope the OP is using a US card that doesn't charge any forex or ATM fees, in which case the Visa/Mastercard rate would generally beat the Transferwise rate if done on the same day.
Originally Posted by
skywardhunter
It almost definitely would not. TransferWise uses the mid-market spot rate which is pretty much the very best possible rate you can ever get. Though cards may not have a Forex fee the exfhaexc rate is likely 1-2% below the mid-market spot rate
I do both of these all the time.
Which one is cheaper tends to be a crapshoot, though if forced to guess I'd say that Transferwise is usually cheaper. Visa/MC exchange rates change once a day, whereas Transferwise updates their rate much more often. Transferwise gets a little less than 1% in fees for USD -> GBP, but Visa/MC's rate is generally off by around 1%. Either way, we're talking a tiny difference--maybe enough to buy a couple cups of coffee--unless there's a major exchange rate fluctuation during the day or you're moving amounts of money that are too high to get out of an ATM and more than I'd want to schlep around in GBP 20 notes
OP, it sounds like you trust the B&B owner, so if you don't want to deal with a stack of 20s I'm sure she'd be happy for you to send payment with a bank transfer, which you can do easily with Transferwise.