MMA Weight Classes Explained
MMA is a combat sport that includes 14 weight classes issued by the “Unified Rules of MMA”. Each athlete has to pick the weight class they are going to compete in according to their physical size and ability to cut weight. But how do MMA weight classes actually work?
MMA weight classes are weight limits created to make matches safe and fair. Each fighter needs to compete within the upper and lower weight limits of the division they choose to compete in. This means that fighters within one weight class are similar in weight, and size which makes matches safe and equal.
Bear in mind that, in modern MMA, there are 14 weight classes proposed by the Unified Rules. But, promotions like the UFC or Bellator are not obligated to include them all. No, this is why UFC has “just” 8 divisions for men and 4 four female fighters.
In this article, you will learn all about MMA weight classes, and how this system works in practice.
How do MMA weight classes work? (Explained)
There are 14 weight classes in total and each one has upper and lower weight limits. Each fighter needs to choose a division from the list below to compete in, according to their weight and size:
| Weight Class | Lower weight limit | Upper weight limit |
| Strawweight | / | 115 lbs (52.2 kg) |
| Flyweight | 115 lbs (52.2 kg) | 125 lbs (56.7 kg) |
| Bantamweight | 125 lbs (56.7 kg) | 135 lbs (61.2 kg) |
| Featherweight | 135 lbs (61.2 kg) | 145 lbs (65.8 kg) |
| Lightweight | 145 lbs (65.8 kg) | 155 lbs (70.3 kg) |
| Super Lightweight | 155 lbs (70.3 kg) | 165 lbs (74.8 kg) |
| Welterweight | 165 lbs (74.8 kg) | 170 lbs (77.1 kg) |
| Super welterweight | 170 lbs (77.1 kg) | 175 lbs (79.4 kg) |
| Middleweight | 175 lbs (79.4 kg) | 185 lbs (88.5 kg) |
| Super Middleweight | 185 lbs (88.5 kg) | 195 lbs (88.5 kg) |
| Light Heavyweight | 195 lbs (88.5 kg) | 205 lbs (93.0 kg) |
| Cruiserweight | 205 lbs (93.0 kg) | 225 lbs (102.1 kg) |
| Heavyweight | 225 lbs (102.1 kg) | 265 lbs (120.2 kg) |
| Super Heavyweight | 265 lbs (120.2 kg) | No limit |
For example, a fighter who walks at around 200 pounds outside the competition usually cuts down to compete in the 185 division. A fighter who weighs 170 pounds usually competes in the 155 division, and the process is the same for all other weight classes.
A day before the fight, the Athletic Commission would arrange official weigh-ins. Each fighter needs to hit the scale within the limits of the weight class they signed to compete in. For example, the upper limit for the lightweight division is 155 pounds (70.4kg), while the lower limit is 145 pounds (66kg). Fighters who compete in this division must step on the scale at 155 or less, but also make sure to be above 145 pounds. It’s that simple.
Unified Rules give the promotions 14 different weight classes they are allowed to adopt. However, the promotions do not have to include all the divisions. The UFC for example has 12 in total (8 for men; 4 for females). But this is just a part of their policies and they can add more weight divisions whenever they want.
But why do UFC weight classes exist?
MMA weight classes exist for two main reasons: to make competition fair and safe. These categories make sure that MMA fighters who compete against each other are similar in weight and size. It prevents physically very big and powerful fighters, to enjoy a big advantage over much smaller and weaker opponents. The power of their strikes, takedowns, or grappling attacks is simply too big for a smaller fighter to handle, which is both dangerous and unfair.
Just imagine the world without the weight limits where you have Francis Ngannou facing Charles Oliveira or Kamaru Usman. Despite the fact that Oliveira is more technical and faster on the feet, he would stand no chance. Ngannou would need to grab just a single part of Oliveira’s body to get him in trouble, or partially land a strike to hurt him and cause severe injuries. In fact, it could easily end up being lethal. This scenario would happen every single time such a physically big fighter faces a smaller opponent in the ring, octagon, or on the streets.
So weight classes make sure that the playground is equal by forcing the fighters to compete within the specified weight limits.
Can MMA fighters move up and down in weight classes?
Yes, MMA fighters are allowed to move up or down in weight if they are not comfortable competing in a certain weight class. Or in modern times, you can often see UFC champions moving a division up or down to fight a champion of that weight class and win another belt. The best example was when Conor McGregor won the 145-pound belt and then moved up to the 155-pound weight class to fight and beat Eddie Alvarez and win the second title. But, they may do this for other reasons as well.
Why do UFC fighters move a division up?
In most cases, fighters move a division up because they no longer can make weight without consequences. The change usually comes when they miss weight a couple of times, or after some health complications during the weight cutting process. The amount of weight they need to lose has become too dangerous, or it has a negative impact on their performance in a fight. Once they step inside the cage, they might feel weak and gas out quickly. In other cases, they might lose the ability to absorb shots like they used to because of the weight cut.
Why do UFC fighters move a division down?
Some fighters, due to their small body frame, might have a hard time dealing with physically bigger opponents in their division. A couple of losses would quickly force them to leave and test their luck in a division down. In some cases, they end up enjoying a solid physical advantage over the opponents and with that, have a lot of success.
When did MMA adopt the concept of weight classes?
MMA weight classes emerged with the creation of “Unified Rules of MMA”. Back in 2000, the Unified Rules were put together by the New Jersey State Athletic Commission. It all started with 12 weight classes but they would add two more a couple of years later. This was a huge moment in MMA history because, during the period without strict weight limits, MMA events were barbaric slugfests and illegal in most US states and countries around the world. In order to exist, the sport needed to change.
Setting strict weight limits and forcing the fighters to compete against people similar in weight and size was a game changer. It boosted the safety of the matches, and made competition fair and even. All of sudden, MMA has become a real combat sport just like boxing and kickboxing, and with that, accepted in the eyes of the mainstream audience. In some way, you can say that the sport wouldn’t exist without Unified Rules and weight classes. It is the single most important rule officials have developed.
When did the UFC weight classes emerge?
The UFC introduced the initial concept of weight classes back on February 7, 1997, at the famous UFC 12 event. Before that, UFC events were open weight tournaments where fighters competed against each other regardless of their size. The weight difference in some of these matches went up to 100 pounds and more, which was very dangerous.
But in 1997 at UFC 12, the UFC decided to separate all fighters on their roster into two weight classes. The heavyweight division was for all the fighters who were above 200 pounds. Lightweight was for fighters below 200 pounds. But just two events later at UFC 14, Lightweight division would be re-named to middleweight, and then at UFC 16, the UFC would add a welterweight division for fighters who are 170 pounds or below. Two years later, they would introduce the bantamweight division (155 pounds or less) at UFC 26, and it stayed that way before the Unified Rules came around in 2000.
The UFC was the first to adopt the Unified Rules, and the first event that was actually organized in alignment with these rules was “UFC 31”.
Why are MMA weight classes different from boxing?
MMA has 14 weight classes while boxing has 18. In reality, however, the gap in weight classes between these two combat sports is even bigger because most MMA promotions do not include more than 8 divisions while most boxing promotions have all of them, 18. Further, the division names are the same, but the weight actually differs a lot. Each division in MMA is around 25 pounds heavier than the same one in boxing. For example:
| Weight Class | Boxing | MMA |
| Heavyweight | Unlimited | 265 lbs (120 kg) |
| Light Heavyweight | 175 lbs (79 kg) | 205 lbs (93 kg) |
| Middleweight | 160 lbs (72.5 kg) | 185 lbs (84 kg) |
| Welterweight | 147 lbs (66.5 kg) | 170 lbs (77 kg) |
But why there is such a big difference between boxing and MMA weight classes?
To be honest, there is no clear explanation for these differences. One explanation is that boxing and MMA are two different sports and types of businesses. MMA promotions like the UFC prefer to run their business with less weight classes and less champions. This allows them to focus more on promoting the entire roster and making all of their champions relevant.
But, there is another reason. Back when MMA started to rise, there was only an open weight division where all fighters, regardless of the size, could come in and compete against each other. Later on in the 90s, the UFC would a 200-pound weight class to separate heavyweight and lightweight fighters. They would work their way down once again by adding a 170 division (UFC 16), and the bantamweight division at UFC 26. When the Unified Rules came around, they just upgraded the existing concept.
To sum it up, there is no exact reason why, it all happened organically as the sport was developing.
How do UFC fighters cut weight?
UFC fighters lose up to 30 pounds in less than a week by following a strict dehydration process. It all starts around 6 days before the fight when they take around 10 gallons of water to get their bodies into a “flushing mode”. Next, they would decrease the amount of water they take over the next four days all the way down to 0.25 gallons until Friday. On Friday, would drink no water at all up until the weigh-ins on Saturday.
In the meantime, they cut the intake of carbohydrates to 50 grams a day and must avoid salt intake at all costs. It is a very dangerous process that, if not done right, may harm your health in the long run, and even be lethal.
Why do UFC fighters cut weight?
In theory, UFC fighters go through a grueling process of losing up to 30 pounds in less than a week just to compete in a weight class below their natural one. This gives them a big physical advantage over their opponents in lower weight classes. On paper, being heavier allows you to hit a much bigger force, and having a higher reach also increases your chances of winning.
In reality, however, weight cutting is done by every single MMA athlete. So instead of competing against a smaller opponent, most MMA fighters would end up facing a fighter similar to their size.
