This might be a very easy thing but still
For example:
The price rises from $2500 to $3000, this in an increase of 1.15%.
So should I do 1.15*(the bitcoin amount I have now at the price of 2500) ?
This is simple math, use this equation its very easy to use.
$2500 - 100%
$3000 - x%
now:
x = (3000 * 100) / 2500 = 120%
So u had 100%, now u have 120% so u gained 20%