MMA Weight Classes Explained: Limits, Weigh-Ins and Missed Weight

MMA weight classes are fixed bodyweight limits, from 115 lb (52.2 kg) for women's strawweight to 265 lb (120.2 kg) for heavyweight. In the UFC, a fighter must be at or under the limit at the official weigh-in, held the day before the fight. In a non-title bout the allowance is one extra pound; a title fight is held to the stated limit.

That is the short version. The rest of this guide covers the limits division by division, how a weigh-in actually works, and what happens when someone misses weight, so you can read a fight card with the right context.

The UFC weight classes, from lightest to heaviest

The UFC runs twelve divisions: eight for men and four for women. They follow the weight classes of the Unified Rules of Mixed Martial Arts, published by the Association of Boxing Commissions (ABC), which also lists smaller and in-between classes such as atomweight (up to 105 lb) and super lightweight (over 155 to 165 lb). A "lightweight" is therefore capped at 155 lb on any card run under those rules.

Division	Limit (lb)	Limit (kg)	Who competes
Strawweight	115	52.2	Women
Flyweight	125	56.7	Men and women
Bantamweight	135	61.2	Men and women
Featherweight	145	65.8	Men and women
Lightweight	155	70.3	Men
Welterweight	170	77.1	Men
Middleweight	185	83.9	Men
Light heavyweight	205	93.0	Men
Heavyweight	265	120.2	Men

One detail trips people up: in the UFC, strawweight exists only as a women's division, so there is no men's equivalent. Women also compete at flyweight, bantamweight and featherweight, at the same limits as the men.

The gaps between classes are not even. Going from welterweight (170) to middleweight (185) is 15 lb, while heavyweight covers everything over 205 lb up to 265 lb, a 60 lb band. Under the Unified Rules, anyone above 265 lb falls into a super heavyweight class that the UFC does not use.

Browse fighters by division

If you want to see who actually competes in each class, AllCombats has a page per division with fighters and their records. Start with the lightweight division, then compare it with the welterweight and middleweight pages. The lighter end has its own page too: flyweight.

How a weigh-in works

UFC official weigh-ins take place the day before fight night: athletes must step on the scale between 9 a.m. and 11 a.m. local time. A fighter who misses on the first attempt may get up to one extra hour, depending on the athletic commission running the event. The televised ceremonial weigh-in is a separate show, not the official one. Other organisations and commissions set their own procedures, so the event details are the reference.

This gap is the whole point of weight cutting. Many fighters walk around well above their division limit and drain water in the final days to hit the number, then rehydrate. In a 2017 study of seven UK mixed martial artists (Matthews and Nicholas, International Journal of Sport Nutrition and Exercise Metabolism), the athletes lost 5.6 kg on average (8% of body mass) in the days before the weigh-in, then regained 7.4 kg (11.7%) over the roughly 32 hours between the weigh-in and the fight. A fighter listed at 155 lb on the scale can therefore step into the cage well above it.

The one-pound rule

Non-title fights allow one pound over the division limit. A lightweight can weigh in at 156 and the bout still counts as a lightweight fight. In a championship bout, both fighters must make the stated limit, so a lightweight champion has to be at 155 or under. The UFC states this on its weight class guide, and the ABC Unified Rules likewise grant a one-pound allowance except in championship fights.

Hydration and safety

The UFC Anti-Doping Policy follows the World Anti-Doping Agency list, which prohibits intravenous infusions above 100 mL per 12 hours unless they are part of legitimate hospital treatment. That is why IV rehydration after the weigh-in is off the table. Nevada rules also cap weight loss after the initial weigh-in at 2 pounds, to be completed within one hour of it. The rules in your state or country are set by the athletic commission running the event.

What happens when a fighter misses weight

Missing weight does not automatically cancel a fight. According to the UFC, the fighter may forfeit a percentage of the purse to the opponent, negotiate a catchweight bout, or in some cases see the fight cancelled. The usual outcomes:

1. Catchweight bout. Both sides agree to fight at a weight between the two divisions. The opponent can refuse and the card changes. Under the ABC Unified Rules, if the two fighters end up in different classes after a miss, the heavier one may not exceed the lighter one by more than five pounds, and a commission can deny a catchweight bout it considers unsafe.
2. A fine. A share of the purse goes to the opponent. At UFC 327 (Miami, April 2026), Chris Padilla weighed 158 lb for a 155 lb lightweight fight, two pounds over the 156 lb non-title maximum, and was fined 20 percent. At UFC 321, one featherweight who was a pound over the non-title maximum paid 20 percent, and a flyweight three pounds over it paid 30 percent. The fine tends to grow with the size of the miss.
3. Title implications. A title fight has no extra pound. At UFC 274 in May 2022, Charles Oliveira missed the 155 lb lightweight limit by half a pound and was stripped of the belt.

For viewers, this means the printed card is not final until weigh-ins end. Check the schedule again the evening before an event rather than relying on a card announced weeks earlier.

Boxing is different: 17 classes and finer steps

Professional boxing uses seventeen traditional divisions, with smaller gaps. A few anchor points: flyweight is 112 lb, featherweight 126 lb, lightweight 135 lb, welterweight 147 lb, middleweight 160 lb, super middleweight 168 lb, light heavyweight 175 lb and cruiserweight 200 lb. Heavyweight is anything above that. The World Boxing Council lists eighteen divisions because it also recognises bridgerweight, with a 224 lb limit.

So the same name does not mean the same weight across sports. A boxing lightweight (135) is 20 lb lighter than an MMA lightweight (155), and a boxing welterweight (147) is 23 lb lighter than an MMA one (170). Comparing fighters across sports by class name alone gives the wrong picture. The boxing page lists boxing events separately from MMA for this reason.

Why weight class matters when you follow fights

Knowing the division changes how you read a card:

1. Records mean different things. A 10-0 fighter at flyweight and a 10-0 fighter at heavyweight faced opponents of very different size and speed, so compare records inside one division.
2. Moving up or down is news. A fighter changing class usually signals a weight-cut problem, a lack of opponents or a title chase.
3. Rankings are per division. Pound-for-pound lists are opinion; division rankings and title lines are not.
4. Promotions share the language. When you compare the UFC with PFL or smaller organisations, the same class names make cards easy to compare.

FAQ

What is the lightest UFC weight class?

Women's strawweight, at 115 lb (52.2 kg). There is no men's division below flyweight (125 lb).

What is the heaviest UFC weight class?

Heavyweight, with a limit of 265 lb (120.2 kg). The UFC has no division above it.

Can a fighter be over the limit in a UFC fight?

Only by one pound in a non-title fight. Anything more is a miss, which usually leads to a catchweight bout and a fine.

Are MMA and boxing weight classes the same?

No. The names overlap but the limits differ. MMA lightweight is 155 lb, boxing lightweight is 135 lb.

When do fighters weigh in?

In the UFC, the day before the fight, between 9 a.m. and 11 a.m. local time. Other organisations and commissions set their own schedule.

Check who is fighting next

Once you know the class, find the card. The AllCombats calendar lists upcoming events across MMA, boxing and other combat sports, so you can follow a division without checking each promotion separately. For a specific athlete, browse the fighters directory.

Sources

1. Association of Boxing Commissions and Combative Sports, Unified Rules of Mixed Martial Arts, weight classes and allowances, August 2025 edition, abcboxing.com
2. UFC, "Understanding UFC Weight Classes", weight classes, weigh-in times, one-pound allowance and missed weight, ufc.com
3. Nevada Athletic Commission, Nevada Rules of Unarmed Combat, NRUC 3.015 (mixed martial arts weight classes and weight loss after weigh-in), 2024 edition, boxing.nv.gov
4. Matthews J. J. and Nicholas C., "Extreme Rapid Weight Loss and Rapid Weight Gain Observed in UK Mixed Martial Arts Athletes Preparing for Competition", International Journal of Sport Nutrition and Exercise Metabolism, 27(2), 2017, pubmed.ncbi.nlm.nih.gov
5. World Anti-Doping Agency, Prohibited List, method M2 (intravenous infusions), wada-ama.org
6. World Boxing Council, "The 18 divisions of boxing", wbcboxing.com
7. UFC 327 event record, weigh-in results of 10 April 2026, en.wikipedia.org
8. UFC 321 event record, weigh-in results, en.wikipedia.org
9. UFC 274 event record, weigh-in results of May 2022, en.wikipedia.org