When you look at the career of "The Notorious," it’s kinda wild how much his body has shifted over the years. Honestly, if you saw him during his early days in Dublin compared to the hulking figure he cuts now in 2026, you’d barely recognize him. People always ask, what weight class was Conor McGregor, but the answer isn't just one number on a scale.
He didn't just fight in one division; he essentially conquered two and experimented with a third, becoming the first person in UFC history to hold two belts at the exact same time. It’s a feat that changed the sport forever, but it also took a massive toll on his health during those brutal weight cuts.
The Featherweight Sniper (145 lbs)
This is where the legend started. In the UFC, McGregor’s primary home for years was the featherweight division (145 lbs). To make that weight, he had to look like a ghost. If you go back and watch the weigh-ins for his fight against Jose Aldo at UFC 194, he looked completely gaunt. Sunken cheeks, ribs showing, the whole bit.
His coach, John Kavanagh, has often talked about how difficult those 145-lb cuts were. Despite the physical struggle, he was a monster at this weight. He went 7-0 in the UFC featherweight division.
- Key Victory: The 13-second knockout of Jose Aldo.
- The Struggle: He was essentially cutting from a "walk-around" weight of about 170 lbs down to 145.
- The Result: He became the undisputed king of the 145-pounders before ever losing a fight in the promotion.
Dominating the Lightweights (155 lbs)
Most experts, including guys like Joe Rogan and Daniel Cormier, have argued that lightweight (155 lbs) is actually McGregor’s "natural" fighting weight. It’s where he looks the most proportional—fast enough to move but heavy enough to carry that "touch of death" in his left hand.
Basically, he did in the UFC what he had already done in Cage Warriors. He moved up to challenge Eddie Alvarez at UFC 205 in Madison Square Garden. That night is widely considered the peak of his technical skills. He looked effortless. He wasn't drained from a massive weight cut, and it showed in his movement.
He eventually became the Lightweight Champion, making him the "Champ Champ." But his history at 155 is a bit of a mixed bag compared to featherweight. While he reached the summit, he also had those high-profile losses to Khabib Nurmagomedov and Dustin Poirier at this weight.
The Welterweight Experiments (170 lbs)
Then things got weird. Most people forget that some of his biggest pay-per-view hits happened at welterweight (170 lbs). He didn't move to 170 because he was a natural welterweight; he did it mostly for convenience or specific rivalries.
Take the Nate Diaz saga. The first fight at UFC 196 was supposed to be at lightweight, but when Rafael dos Anjos pulled out and Diaz stepped in on short notice, they just agreed to fight at 170 so neither had to kill themselves cutting weight. McGregor actually weighed in at 168 lbs for that first Diaz fight. He looked "soft" compared to his usual shredded self.
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He later returned to 170 to fight Donald "Cowboy" Cerrone in 2020. By that point, he had put on significant muscle mass. It’s a weight class where he doesn't have the massive size advantage he enjoyed at featherweight, but he certainly didn't have to suffer through a training camp of starvation.
A Quick Reality Check on the Numbers
To keep it simple, here is how the divisions break down for him:
Featherweight (145 lbs): This was his "skinny" phase. He never lost a fight here.
Lightweight (155 lbs): His championship weight. He holds a 1-3 record in the UFC at this weight, which is a bit surprising given he was the champ.
Welterweight (170 lbs): His "big man" phase. He’s 2-1 here, with wins over Diaz and Cerrone.
Why His Weight Matters So Much Now
The reason everyone keeps track of what weight class was Conor McGregor is because of his recent physical transformation. Since his leg injury against Poirier in 2021, he’s bulked up significantly. There’s been a ton of speculation that he might even try to compete at middleweight (185 lbs), though most analysts think that’s a stretch for his 5'9" frame.
Walking around today, he looks closer to 190 lbs of pure muscle. For a guy who used to make 145, that is a staggering amount of weight to carry. It changes his cardio, his speed, and how his joints handle the stress of a fight.
Honestly, the "Champ Champ" era was a moment in time that probably won't be repeated with the same level of hype. He manipulated the scales better than almost anyone in the game, using his size to bully featherweights and his speed to outclass lightweights.
If you're looking to understand his career, don't just look at the belts. Look at the weigh-in photos. They tell the real story of a guy who pushed his body to the absolute limit across three different divisions.
What You Can Take Away From This
If you're a fan or a casual viewer, the big takeaway is that McGregor's versatility was his greatest asset. He wasn't just a "featherweight" or a "lightweight." He was a prize fighter who followed the biggest opportunities, regardless of what the scale said.
For your own training or sports interest, notice how much his fighting style changed with the weight. At 145, he was a twitchy, distance-managing sniper. At 170, he became more of a power puncher. Changing weight classes isn't just about eating more or less; it’s about fundamentally rebuilding how you move.
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Track his next move closely. Whether he lands back at 155 or tries a final run at 170, the "what weight class" question will always be at the center of the McGregor conversation.
Next Steps for Fans:
- Watch the UFC 194 weigh-ins vs. the UFC 246 weigh-ins to see the 25-pound difference in his frame.
- Compare his striking speed in the Max Holloway fight (145 lbs) to the second Poirier fight (155 lbs).
- Follow his current training footage to see if he’s leaning out for a return to lightweight or staying heavy for a welterweight bout.