Create a calculated percentage field to increase price

I have 3 fields to help achieve this calculation.

1.) Price - Calculated field (Price base + Price Increase%)

2.) Price Base - User adds contract price here

3.) Price Increase(%) - Number which indicates percentage being added on to the Price Base

I have tried a formula already which is: ifElse(equal($price_increase_c,""),multiply(1.05,$price_base_c),0)

Do i have to manually add each possible percentage increase in or is there a function i can use to help make this easier?