If you are buying the EUR against the USD, any profit and loss from this trade is due to the conversion rate of EUR to USD and the P&L for this trade is converted to USD terms in real time. The P&L of a pip is always dependent on the size of the trade or volume of the trade and size of the pip.
Pip Profit/Loss = Trading volume x pip size
In the case of the EURUSD:
1 pip = 100,000 x 0.0001 = USD 10
This means that in a trade with a volume of EUR 100,000, each pip up or down in the price will result in a USD 10 profit or loss.