Now you need to decide to what is a more realistic income projection. What percentage of your Target Market do you think will actually buy the app? Remember, even if you build a great app, you can't expect everybody to buy it.
If you have no real idea about this, then 1% is a good starting place. This means that one in every hundred will buy the app.
That might seem like a small figure but there are other aspects to consider too, such as marketing (how many people in your Target Market will get to hear about your product) and competition (how many people will choose to buy a competing product before, or instead of buying yours).
This number is called your Uptake Percentage.
Calculate your Uptake Percentage