It's hard question to answer. Some of them can't be compared the same because of different time they were playing in. I am a strong believer that Magnus if faced today against previous WC in their prime would definitely beat all of them in a match (12 or 24 games). Simply because chess has evolved so much even since Fisher era. But if they all lived today or all competed at the same time, everything would be different and unfortunately there is no way to know who is the stronger/weakest of them all. I read nice article describing this and comparing them properly so I will look for it and when I find it I will post it here.
Who is/was the weakest World Champion ever?

Who Was The Best World Chess Champion In History? - https://chess.com/article/view/who-was-the-best-world-chess-champion-in-history This is the article I mentioned in #2. If you have time for reading make sure to also check these two, they are great! All The World Chess Champions - https://chess.com/article/view/world-chess-champions and The Best Chess Players Over Time - https://chess.com/article/view/the-best-chess-players-over-time

Karpov and Kasparov were both beasts as champion, domineering like no one since Alekhine.

EBowie is correct. If you just use quality of play as a metric, Steinitz is by far the worst world chess champion: lots of errors, lots of blunders, and lots of inaccuracies compared to the rest. If you put all of the chess champions in a room at their peak and had a tournament, he would surely come in last.

Maybe so but in his defense chess was transitioning from the romantic Era to the modern Era so he gets a pass.

Compared to engine analysis, my guess would be Steinitz.
It is unfair today athletes vs athlete from 100 years ago.
e.g Fastest runners from 100 years ago took nearly 3 hours to finish a marathon, but 2 hours for today.
https://www.youtube.com/watch?v=8COaMKbNrX0&ab_channel=TED
With today's standard, Steinitz could be around 2500 and Paul Morphy could be around 2600.

Not counting engine analysis of course.
Makes no sense. Isn't that the most accurate way of measuring strength?

You have to define what "weakest" means. Are you talking about weakest for their time period, or weakest in a vacuum?
The latter leads to an easy answer - Steinitz, the first world champion. So I'm guessing you're referring to the former, which is a more interesting question.


Ebowie...weakest against peers during that time etc. Obviously chess was played worse a long time ago. Steinitz was during a chess transition from romantic chess to modern chess so a lot of people made mistakes back then.
Carlsen without a doubt. If you put carlsen in the 1960’s and 1970’s with no computer analysis to use as a crutch he would legit not even be a top 10 player

Carlsen without a doubt. If you put carlsen in the 1960’s and 1970’s with no computer analysis to use as a crutch he would legit not even be a top 10 player
Well, the people he's been dominating for years have some of that too.
Carlsen without a doubt. If you put carlsen in the 1960’s and 1970’s with no computer analysis to use as a crutch he would legit not even be a top 10 player
Well, the people he's been dominating for years have some of that too.
Exactly, Carlsen is only world champion because he is playing in the weakest era of talent ever.
I would say Max Euwe.
He held on to the World Title shorter than anyone. (1935-37) And did not reclaim it, like
the Great Botvinnik did twice, once against Euwe and once against the Brilliant Tal
https://en.m.wikipedia.org/wiki/Max_Euwe