MMA weight classes group fighters by size so that bouts are fair, but the same division name doesn’t always mean the same weight. A welterweight in the UFC fights at up to 170 pounds, while a welterweight in ONE Championship can weigh up to 185. This guide covers both promotions and explains why their limits differ. For fight results and news on Filipino fighters, follow our UFC and MMA coverage.
21+
Betting is for adults 21 and over. Bet responsibly. Need help? Call the National Problem Gambling Helpline at (02) 8248 9568.
What are MMA weight classes?
A weight class sets the maximum weight a fighter can weigh at the official weigh-in. The Unified Rules of MMA, used by commissions in North America, list 14 classes, from strawweight at 115 pounds to super heavyweight with no upper limit. The strawweight class was added in 2015, and four “super” classes were added in 2017.
Each promotion chooses which of those classes to use, so no major promotion uses all 14. Boxing works on the same principle but with more divisions; our guide to boxing weight classes explains its 17 divisions and title belts.
The four classes added in 2017 sit between the traditional divisions: super lightweight at 165 pounds, super welterweight at 175, super middleweight at 195, and cruiserweight at 225. Few major promotions use them, but they give regional events and commissions more options when matching fighters.
UFC weight classes
The UFC uses 12 divisions: eight for men and four for women. Each division has its own champion and rankings, and strawweight is the only division that is for women only.
| Division | Weight limit | Men | Women |
|---|---|---|---|
| Strawweight | 115 lb (52.2 kg) | ✓ | |
| Flyweight | 125 lb (56.7 kg) | ✓ | ✓ |
| Bantamweight | 135 lb (61.2 kg) | ✓ | ✓ |
| Featherweight | 145 lb (65.8 kg) | ✓ | ✓ |
| Lightweight | 155 lb (70.3 kg) | ✓ | |
| Welterweight | 170 lb (77.1 kg) | ✓ | |
| Middleweight | 185 lb (83.9 kg) | ✓ | |
| Light heavyweight | 205 lb (93.0 kg) | ✓ | |
| Heavyweight | 265 lb (120.2 kg) | ✓ |
The women’s featherweight division still exists, but it has been inactive for long stretches because of a small number of fighters at that weight. The UFC does not use the Unified Rules’ super lightweight, super welterweight, super middleweight, or cruiserweight classes.
UFC divisions and rankings
All UFC divisions have their own champion and a ranked top 15, so a fighter can only climb toward a title shot within their own weight class. Heavyweight is the only division with a minimum as well as a maximum: fighters must weigh more than 205 pounds, the light heavyweight limit, to compete there.
Some of the sport’s biggest names have won titles in two UFC divisions at once. Conor McGregor became the first to hold two UFC titles at the same time in 2016, and Amanda Nunes later held the women’s bantamweight and featherweight titles together.
Non-title fights and catchweights
In non-title fights, the limit is usually one pound above the division limit, so a lightweight bout allows fighters up to 156 pounds. Title fights must be made at the exact division limit. When both sides agree, a fight can also be held at a catchweight, a weight between two divisions.
ONE Championship weight classes
ONE Championship, the Asian promotion followed closely by many Filipino fans, uses different weight limits for divisions with the same names. Its men’s divisions start at strawweight, 125 pounds, and go up to heavyweight, 265 pounds, while its women compete at atomweight and strawweight. ONE also stages Muay Thai, kickboxing, and submission grappling, which have their own weight classes, so the table below covers MMA only.
| Division | ONE weight limit |
|---|---|
| Atomweight (women) | 115 lb (52.2 kg) |
| Strawweight | 125 lb (56.7 kg) |
| Flyweight | 135 lb (61.2 kg) |
| Bantamweight | 145 lb (65.8 kg) |
| Featherweight | 155 lb (70.3 kg) |
| Lightweight | 170 lb (77.1 kg) |
| Welterweight | 185 lb (83.9 kg) |
| Middleweight | 205 lb (93.0 kg) |
| Light heavyweight | 225 lb (102.1 kg) |
| Heavyweight | 265 lb (120.2 kg) |
Why ONE’s limits are higher
ONE uses a hydration test during fight week to stop fighters from losing large amounts of weight through dehydration. Because fighters compete closer to their natural walking weight, ONE set each division about one class higher than the Unified Rules equivalent. Our guide to MMA rules and scoring explains the hydration test and other ways ONE differs from the UFC.
UFC vs ONE Championship weight classes compared
The table below shows how far apart the two promotions are. In most cases, ONE’s limit matches the UFC’s next division up.
| Division name | UFC limit | ONE limit |
|---|---|---|
| Strawweight | 115 lb | 125 lb |
| Flyweight | 125 lb | 135 lb |
| Bantamweight | 135 lb | 145 lb |
| Featherweight | 145 lb | 155 lb |
| Lightweight | 155 lb | 170 lb |
| Welterweight | 170 lb | 185 lb |
| Middleweight | 185 lb | 205 lb |
| Light heavyweight | 205 lb | 225 lb |
| Heavyweight | 265 lb | 265 lb |
Key takeaway
When a fighter moves between the UFC and ONE, the division name can change even if their weight doesn’t. A UFC lightweight at 155 pounds would usually compete at featherweight in ONE.
How fighters choose a weight class
Most fighters compete in the lightest division they can make safely, since being the bigger and stronger fighter is an advantage. Their frame, natural walking weight, and how much weight they can cut before a weigh-in all play a part.
Fighters often move up a division as they get older, when cutting weight becomes harder, or move down in search of a size advantage. Each move is a risk, because it changes how their speed, power, and durability compare with the new opponents they face.
Weigh-ins and missing weight
In the UFC, fighters weigh in the day before the event and then rehydrate before the fight. A fighter who misses weight is usually fined part of their purse, and a champion or challenger who misses weight for a title fight cannot win the belt. ONE combines its weigh-in with the hydration test during fight week, and a fighter must pass both to be cleared to compete.
Bouts can still go ahead at a catchweight if both camps agree, or they can be cancelled. Our guide to how the UFC works covers weigh-ins, rankings, and title shots in more detail.
Filipino fighters and the weight classes
Filipino fighters have had their greatest success in ONE Championship’s lighter divisions. Joshua Pacio is the three-time and current ONE strawweight world champion, competing at 125 pounds, and he extended his run with a submission win on July 10, 2026. His division’s 125-pound limit is 10 pounds above the UFC’s strawweight limit.
Pacio rose through Team Lakay, the Baguio City gym that produced several ONE world champions, before moving to Lions Nation MMA in 2023. The lighter weight classes remain where Filipino fighters are most active on the international stage.
How weight class affects fights and betting
Weight class shapes how fights tend to play out. Lighter divisions often feature faster pace and more fights that go to the judges, while heavier divisions tend to end by knockout more often, which matters for method-of-victory and total rounds markets.
Fighters moving up or down a division also add uncertainty, since their record at the old weight may not carry over. Our MMA betting guide explains how these markets work. Betting is for adults aged 21 and over.
