Upvote:5
You're extraordinarily unlikely to be asked to show how much money you have available.
As a British citizen, the general process for you entering the USA at an airport will be to go to an Automated Passport Control kiosk, insert your passport, scan your fingerprints, touch the customs declaration questions on screen, then take your passport and receipt to the desk where an officer will look at them, ask you a couple of brief questions, and send you on to baggage claim.
If your receipt prints with a big X, then you are probably going to have a long conversation with CBP. In that case, you might be asked about finances, depending on the specific reason for the referral.
So, the question is, how do you demonstrate how much money is available to you?
Upvote:7
Reposting from comments as advised.
Out of the four times I've been through JFK, only once was I asked about finances during my stay. The officer asked how much cash I had on me, I told him $10, which was left over from my last trip, he laughed and asked what I would use whilst I'm visiting, I simply told him I was going to an ATM to withdraw due to better exchange rate. He nodded and that was that, no proof needed.
If you are worried about having proof, a bank statement, window open on your phone to online banking, or having your cash ready to show would all be acceptable. Really the question is there to ensure you won't need any government support during your visit.