Become the very best, like no one ever was. This is your goal in Pokemon GO, and in life. But mostly Pokemon GO right now. To fulfill that goal, you’ll need to raise a strong batch of Pokemon, which means understanding CP, the CP cap, and that little CP circle behind your Pokemon.
You can check up on the stats of your Pokemon once you catch them or by tapping them from the Pokemon collection page. You’ll see a white circle surrounding them, filled up to some degree. The line represents their CP, or Combat Points, a number that indicates their strength. As you power up your Pokemon using Stardust and Candy, the semicircle meter will fill, and once the marker reaches the end, your Pokemon has reached their CP cap and can’t gain any additional Combat Points. Though each species has its own CP ranges, your Pokemon’s CP cap will increase as your trainer level goes up.
Each species of Pokemon has a different CP cap, so you’ll see some number:meter variation between your different party members. Your Rattata’s 50 CP may take up half their bar, while a Cubone’s meter will only be filled a quarter way by the same number.
Keep in mind that your Pokemon won’t evolve if you hit max CP. There’s a whole different system for that.