But I bought a stock at 83.84 USD at exchange rate of 0.63 and now the exchange rate is 0.60 and the price of the stock is at 89.30 USD. So this has affected the value of my gain which is less than it could be had the exchange rate stayed at 0.63 or had it gone up to for example > 0.70
So I'm trying to work out how exchange rates affect stock purchases and their value in my portfolio
But I bought a stock at 83.84 USD at exchange rate of 0.63 and now the exchange rate is 0.60 and the price of the stock is at 89.30 USD. So this has affected the value of my gain which is less than it could be had the exchange rate stayed at 0.63 or had it gone up to for example > 0.70
So I'm trying to work out how exchange rates affect stock purchases and their value in my portfolio
If it is for valuation purposes then just mark-to-market the stock which is pretty much what you have already done. The value is the price multiplied (or divided depending on the quote) by the current exchange rate.
But that is one of the pitfalls of buying overseas stocks, as you know have 2 sets of ricks (stock and currency).