The estimated Combat Points are not the exact value your Pokémon will have. Your Pokémon can be stronger or weaker than that estimated value. Therefore, Cp Calculator for Evolution:Go can estimate three type of cp. These are:
Expected cp: It is ideal cp value for trainers who are between about 15-3- levels.
Min cp: Min cp shows that minimum pokemon cp when your pokemon evolve
Max cp: It is maximum cp value of your pokemon can reach after evolution. It usually true for trainers have less level.
How to use:
*Choose pokemon that you want to evolve.
*Set your pokemon's cp