Firm poops and constipation

Hey everyone. A few weeks ago I started only formula feeding, the pediatrician told me that breast fed babies are more likely to get constipated (which I know is completely untrue so I'm not sure why they told me that) since stopping breast feeding he's been having firm poops instead of the regular mushy stuff, he still poops almost every day but it just seems like less and I'm worried about it being painful to him / constipation. So, any tips to help with a constipated formula fed baby? (He's 1 month 17 days)