I bought $30.00 of Bitcoin. The price at that time was $6,896.00. The price now is $8,074.00. How much did I make? And how do I do the math?
30 / 6896 * 8074 = 35.1247099767981
So, you've made a net profit of $5.12., which is (5.12 / 30) a profit margin of 17.06 percent.
For a more indepth answers about realized and unrealized profit/loss for investments, and specifically Bitcoin, check What happens if I buy Bitcoins and the price goes down?