How do you find a pet's overall rating?

If you're trying to get into the Blue Building you need your pets total over all stats (minus level and intelligence) to be 100 that means your Strength, Defence, Health, and Speed must total 100. 25 in all 4 stats will get you that rating.

If you're meaning overall rating not for the blue building, if you go to the page where all your pets are listed, near the bottom of their little square under their stats is 2 numbers: Tier & Rank.

Thank you!