Not really trading ... but say you want to make a transfer overseas ? What is the best way to ensure that you are sending the correct amount (sending USD), given that the rates change ?
I guess it depends on what you want to do. If you buy something, you get it charged in Euros from your CC and then it is converted back when the sale is made. If you want to send some money overseas like 1,000, 5,000 etc...it is based on the current rate or perhaps the previous day's rate. You send the money and it gets converted. Check first. Or, if you are sending to a relative, just send the amount they need plus 1 or 2 percent extra to cover any differences in the rate or any transaction fees. But......check the place you are sending it to. If the dollar is 1.20 to the Euro, it does not mean you will get 10 Euros for 12 dollars. That is the banker's rate. It might cost you 1.21 , 1.22 or worse. Plus a wire fee from this end and perhaps something on the receiving end. How much are you sending? There are limits to how much you can send without having to fill out a form explaining why. Governments have this thing about money laundering , terrorism and drug trafficking these days....
Either use a cushion, or order your bank to transfer x USD from your local currency account... The bank will use realtime currency rates...
Any transfer in or out of the USA is made in USD. So, if you want to send 100xxxxx Euros, ask that the recipient should receive the exact 100xxxx Euros. "They" will add fees, commission and use "their best exchange rate".