Just compare with the price , i usually compare with the USD price to spot how much i made.
You need to maintain a record in which you have you list down all the details regarding buying of the bitcoins which you have in your wallet. Analyze the market price whenever you want to know whether you are going in profit or loss.
Compare the current market price of bitcoin with that amount at which you bought those bitcoins. Taking the difference in between will help you know the current statistics.
I always take notes if I purchase coins from exchange platforms. I write down my buying satoshi values so I don't forget them. I also write down usd value of my buy orders to calculate my profit in the best way.