Peter Capaldi is the 13th actor to portray the Doctor, but the 14th Regeneration of the Doctor

1st Regeneration (R), 1st actor, William Hartnell

2nd R, 2nd actor, Patrick Traughton

3rd R, 3rd actor, Jon Pertwee

4th R, 4th actor, Tom Baker

5th R, 5th actor, Peter Davidson

6th R, 6th actor, Colin Baker

7th R, 7th actor, Sylvester McCoy

8th R, 8th actor, Paul McGann

9th R, 12th actor, John Hurt

10th R, 9th actor, Christopher Eccleston

11th R and 14th R, 10th and 14th actor, David Tennant

12th R, 11th actor, Matt Smith

13th R, 12th actor, Peter Capaldi

14th R, 13th actor, Jodie Whittaker

15th R, 15th actor, Ncuti Gatwa

However, there's also that pesky little thing about David Tennant regenerating himself – of the energy in the hand – again with the same face during the Time Lord-Human Metacrisis in Journey's End, which is what sparked the metacrisis and creation of the human-Time Lord Doctor. So, technically, David Tennant could be said to be the 10th, 11th, and 14th Doctors.

Plus, William Hartnell is the 1st regeneration of the Doctor. That means, he regenerated from some other Doctor. If Chibnall's pre-cannon Doctor is taken as cannon now, then Jo Martin has to be factored into to the list as well.

Family aside, Doctor Who's time line is definitely confusing.

Time Lords…

Whatca gonna do?