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MMA Weight Classes in kg & lb: UFC, ONE & Amateur Chart
By Simon Jounan · Founder of MyFightPrep · Kickboxer & Muay Thai fighter
Published · 7 min read
Contents
MMA weight classes are set in pounds. The Unified Rules of MMA define 15 classes, from atomweight (up to 105 lb / 47.6 kg) to super heavyweight (over 265 lb / 120.2 kg). The UFC uses only some of them: eight men’s divisions from flyweight (125 lb / 56.7 kg) to heavyweight (265 lb / 120.2 kg), plus women’s strawweight, flyweight and bantamweight. Below you’ll find every class in kg and lb, including ONE Championship and amateur (IMMAF) limits, how weigh-ins work, and how to choose your division.
Limits checked: September 2026 — confirm with your event’s current rulebook.
Unified Rules MMA weight classes (all 15)
The Association of Boxing Commissions and Combative Sports (ABC) publishes the official Unified Rules of MMA. The latest version, amended in August 2026, lists these classes (ABC, 2026):
| Class | Range (lb) | Upper limit (kg) | Used by UFC? |
|---|---|---|---|
| Atomweight | up to 105 | 47.6 | No |
| Strawweight | over 105 to 115 | 52.2 | Women |
| Flyweight | over 115 to 125 | 56.7 | Men and women |
| Bantamweight | over 125 to 135 | 61.2 | Men and women |
| Featherweight | over 135 to 145 | 65.8 | Men (women’s not currently ranked) |
| Lightweight | over 145 to 155 | 70.3 | Men |
| Super lightweight | over 155 to 165 | 74.8 | No |
| Welterweight | over 165 to 170 | 77.1 | Men |
| Super welterweight | over 170 to 175 | 79.4 | No |
| Middleweight | over 175 to 185 | 83.9 | Men |
| Super middleweight | over 185 to 195 | 88.5 | No |
| Light heavyweight | over 195 to 205 | 93.0 | Men |
| Cruiserweight | over 205 to 225 | 102.1 | No |
| Heavyweight | over 225 to 265 | 120.2 | Men (UFC: 206–265 lb) |
| Super heavyweight | over 265 | — | No |
The UFC doesn’t use atomweight, the three “super” classes, cruiserweight or super heavyweight. That means any UFC fighter above 205 lb is a heavyweight.
UFC weight classes (men and women)
The UFC describes itself as running 12 weight classes (UFC, 2024). As of September 2026, its official rankings cover 11 of them: eight men’s and three women’s (UFC, 2026).
| Division | Limit (lb) | Limit (kg) | Men | Women |
|---|---|---|---|---|
| Strawweight | 115 | 52.2 | — | Yes |
| Flyweight | 125 | 56.7 | Yes | Yes |
| Bantamweight | 135 | 61.2 | Yes | Yes |
| Featherweight | 145 | 65.8 | Yes | Not currently ranked |
| Lightweight | 155 | 70.3 | Yes | — |
| Welterweight | 170 | 77.1 | Yes | — |
| Middleweight | 185 | 83.9 | Yes | — |
| Light heavyweight | 205 | 93.0 | Yes | — |
| Heavyweight | 265 | 120.2 | Yes | — |
In non-title bouts the UFC allows one pound over the limit (for example 156 lb for lightweight). Title fights must be made at or under the limit (UFC, 2024).
ONE Championship MMA weight classes
ONE uses its own ten classes, the same ones it uses for Muay Thai and kickboxing. The same name usually means a heavier limit than in the UFC: ONE flyweight goes up to 135 lb, which is the UFC bantamweight limit. You also have to make weight while passing a hydration test (ONE Championship, 2026).
| Class | Over | Up to |
|---|---|---|
| Atomweight | 105 lb (47.6 kg) | 115 lb (52.2 kg) |
| Strawweight | 115 lb (52.2 kg) | 125 lb (56.7 kg) |
| Flyweight | 125 lb (56.7 kg) | 135 lb (61.2 kg) |
| Bantamweight | 135 lb (61.2 kg) | 145 lb (65.8 kg) |
| Featherweight | 145 lb (65.8 kg) | 155 lb (70.3 kg) |
| Lightweight | 155 lb (70.3 kg) | 170 lb (77.1 kg) |
| Welterweight | 170 lb (77.1 kg) | 185 lb (83.9 kg) |
| Middleweight | 185 lb (83.9 kg) | 205 lb (93.0 kg) |
| Light heavyweight | 205 lb (93.0 kg) | 225 lb (102.1 kg) |
| Heavyweight | 225 lb (102.1 kg) | 265 lb (120.2 kg) |
So a ONE “lightweight” can weigh up to the UFC welterweight limit.
Amateur MMA weight classes (IMMAF)
IMMAF, the international amateur MMA federation, moved to 12 men’s and 8 women’s categories at its October 2024 World Championships. The change was made to reduce extreme weight cutting (IMMAF, 2024). The kg figures below are as IMMAF publishes them.
| Category | Men | Women |
|---|---|---|
| Atomweight | — | 47.6 kg (105 lb) |
| Strawweight | 52.2 kg (115 lb) | 52.2 kg (115 lb) |
| Flyweight | 56.7 kg (125 lb) | 56.7 kg (125 lb) |
| Bantamweight | 61.2 kg (135 lb) | 61.2 kg (135 lb) |
| Featherweight | 65.8 kg (145 lb) | 65.8 kg (145 lb) |
| Lightweight | 70.3 kg (155 lb) | 70.3 kg (155 lb) |
| Super lightweight | 74.8 kg (165 lb) | 74.8 kg (165 lb) |
| Super welterweight | 79.4 kg (175 lb) | 79.4 kg (175 lb) |
| Middleweight | 83.9 kg (185 lb) | — |
| Super middleweight | 88.4 kg (195 lb) | — |
| Light heavyweight | 93 kg (205 lb) | — |
| Heavyweight | 97 kg (215 lb) | — |
| Super heavyweight | over 97 kg (215 lb) | — |
IMMAF has no plain welterweight (170 lb) any more. Its heavyweight also tops out at 97 kg, far below the pro limit of 265 lb.
In the US, the ABC’s amateur MMA rules use ten classes: flyweight (125 lb and under), bantamweight (126–135), featherweight (136–145), lightweight (146–155), welterweight (156–170), middleweight (171–185), light heavyweight (186–205), cruiser heavyweight (206–230), heavyweight (231–265) and super heavyweight (over 265). Weigh-in procedures are left to the sanctioning commission (ABC, 2011). Whether you fight in the UK, Europe or the US, check which rule set your event runs under before you choose a class.
How MMA weigh-ins work
Pro MMA usually weighs in the day before, which gives you a longer recovery window than most amateur sports. That window is also why pro fighters cut so much.
- UFC: Official weigh-ins take place the day before the fight, between 9 and 11 am local time. If you miss weight, you may forfeit part of your purse to your opponent, the bout may become a catchweight, or it may be cancelled (UFC, 2024).
- Unified Rules: If one fighter misses and the two end up in different classes, the heavier fighter may be no more than 5 lb above the lighter one (ABC, 2026).
- ONE: Weigh-ins happen 24–48 hours before the event, and you must first pass a urine specific gravity test (≤1.025) before your weight counts (ONE Championship, 2026).
The ISSN puts professional MMA in the 24–36-hour weigh-in-to-fight group (Ricci et al., 2025). That time helps, but it doesn’t make a huge dehydration cut safe. Read our guide to rehydrating after the weigh-in to use that window properly.
Quick conversions: where does your weight land?
| Weigh-in weight | UFC / Unified Rules | ONE | IMMAF (men) |
|---|---|---|---|
| 70 kg / 154.3 lb | Lightweight | Featherweight | Lightweight |
| 77.1 kg / 170 lb | Welterweight | Lightweight (at the limit) | Super welterweight |
| 84 kg / 185.2 lb | Light heavyweight (UFC); super middleweight (Unified Rules). Both are just over the 185 lb middleweight limit | Middleweight | Super middleweight |
| 90 kg / 198.4 lb | Light heavyweight | Middleweight | Light heavyweight |
| 100 kg / 220.5 lb | Heavyweight (UFC); cruiserweight (Unified Rules) | Light heavyweight | Super heavyweight |
How to choose your MMA weight class
The right class is the one you can make with a planned, moderate reduction and still wrestle hard in round three. It is not the lightest class you can survive.
- Measure your baseline. Average two weeks of morning weights at normal training intake.
- Compare the gap with the evidence. The ISSN notes that combat athletes are commonly advised to lose about 0.5–1 kg per week in camp. It describes supervised acute water loss of roughly 2–4% of body mass within 24 hours of weigh-in as the optimal range (Ricci et al., 2025).
- Use the in-between classes. If you’re stuck between 155 and 170 lb, a super lightweight (165 lb) bout under the Unified Rules or at IMMAF may suit you better than a brutal cut.
- Set a minimum weight. The ACSM consensus recommends basing a minimum competition weight on body composition and banning unhealthy weight-loss methods (Burke et al., 2021).
- Amateurs: go up if in doubt. Your first fights are for learning, not for winning the scale.
Want your own numbers? The weight cut calculator shows the weekly pace you’d need and what’s left for fight week.
Work out your numbers with how much weight you can safely cut and follow how to cut weight for a fight. For striking-only rule sets, see kickboxing weight classes and Muay Thai weight classes, or the combat sports weight classes overview.
MyFightPrep tracks your weight trend toward the class limit and fight date, so you can see early whether a division is realistic — free.
Important
This guide is general information, not medical advice. Weight classes and weigh-in rules vary by commission and promotion, so confirm them in your bout agreement or rulebook. Rapid dehydration can be dangerous. Never use diuretics, laxatives, vomiting or sweat suits to make weight, and stop if you feel dizzy, confused, faint or cramp up. Amateurs and young fighters should avoid water cuts and choose their class with a coach and a doctor.
Frequently asked questions
What are the 12 weight classes in UFC?
The UFC has described 12 weight classes: eight men's (flyweight 125 lb, bantamweight 135, featherweight 145, lightweight 155, welterweight 170, middleweight 185, light heavyweight 205, heavyweight 265) and four women's (strawweight 115, flyweight 125, bantamweight 135, featherweight 145). As of September 2026, UFC's official rankings list 11 divisions, with no women's featherweight ranking.
What weight is 70 kg in MMA?
70 kg is 154.3 lb, which is lightweight under the Unified Rules, in the UFC and at IMMAF (limit 155 lb / 70.3 kg). In ONE Championship, 70 kg falls in featherweight (145–155 lb), and you would have to make it while passing a hydration test.
Is 90 kg heavyweight in UFC?
No. 90 kg is 198.4 lb, which is light heavyweight (up to 205 lb / 93.0 kg). UFC heavyweight starts above 205 lb and goes up to 265 lb (120.2 kg).
What weight is 170 lbs in UFC?
170 lb (77.1 kg) is the UFC welterweight limit. In non-title bouts the UFC allows one pound over, so 171 lb, while title fights must be made at 170 lb or less.
What is lightweight in kg in MMA?
Lightweight is up to 155 lb, which is 70.3 kg. That applies to the UFC, the Unified Rules and IMMAF amateur competition. ONE Championship's lightweight is different: over 155 up to 170 lb (70.3–77.1 kg).
Sources
This guide is based on the works below. Numbers in the text refer to them.
- Association of Boxing Commissions and Combative Sports (ABC) (2026). Unified Rules of Mixed Martial Arts (amended with rule changes 5 August 2026)
- Association of Boxing Commissions and Combative Sports (ABC) (2011). Association of Boxing Commissions: Amateur Mixed Martial Arts Unified Rules
- UFC (2024). Understanding UFC Weight Classes and Weigh-Ins
- UFC (2026). UFC Athlete Rankings
- ONE Championship (2026). ONE Championship Martial Arts: Weight Classes and Hydration Testing
- International Mixed Martial Arts Federation (IMMAF) (2024). IMMAF to introduce cutting edge weight management policy starting with World Championships in Uzbekistan
- Ricci AA, Evans C, Stull C, et al. (2025). International Society of Sports Nutrition Position Stand: Nutrition and Weight Cut Strategies for Mixed Martial Arts and Other Combat Sports
- Burke LM, Slater GJ, Matthews JJ, Langan-Evans C, Horswill CA (2021). ACSM Expert Consensus Statement on Weight Loss in Weight-Category Sports