Weight classes vary wildly across underground fighting organizations. Some use traditional boxing divisions, others use simplified systems, and many do not use formal weight classes at all. This reference maps every organization's weight structure side by side.
Master Weight Class Comparison Table
Men's Divisions
| Weight Class | Limit | BKFC | BKB | Top Dog | Power Slap | Gamebred | Strelka | RNR | KOTS | Streetbeefs |
|---|---|---|---|---|---|---|---|---|---|---|
| Strawweight | 115 lbs | No | No | No | No | No | No | No | No | Matched |
| Flyweight | 125 lbs | Yes | Yes | No | Flyweight | Yes | No | No | No | Matched |
| Bantamweight | 135 lbs | Yes | Yes | No | Bantamweight | Yes | No | No | No | Matched |
| Featherweight | 145 lbs | Yes | Yes | No | Featherweight | Yes | No | No | No | Matched |
| Lightweight | 155 lbs | Yes | Yes | Light | Lightweight | Yes | No | No | No | Matched |
| Welterweight | 170 lbs | Yes | Yes | Middle | Welterweight | Yes | No | No | No | Matched |
| Middleweight | 185 lbs | Yes | Yes | Heavy | Middleweight | Yes | No | No | No | Matched |
| Light Heavyweight | 205 lbs | Yes | Yes | Super Heavy | Light Heavyweight | No | No | No | No | Matched |
| Cruiserweight | 225 lbs | Yes | No | — | — | No | No | No | No | Matched |
| Heavyweight | 265 lbs | Yes | Yes | — | Heavyweight | Yes | No | No | No | Matched |
Key:
- "Yes" = Formal division exists
- "No" = Division does not exist
- "Matched" = Fighters matched by approximate weight, no formal divisions
- "—" = Included in adjacent division
BKFC note: from welterweight up, BKFC's own limits are lighter than the standard limits in this table — welterweight 165, middleweight 175, light heavyweight 185, cruiserweight 205, plus an Ironweight division at 225 added in July 2026, and an unlimited heavyweight above that. BKFC has no men's strawweight. See the BKFC section below.
Organization-by-Organization Breakdown
BKFC Weight Classes (Most Comprehensive)
| Division | Weight Limit | Champion (bkfc.com, Sept 2026) |
|---|---|---|
| Flyweight | 125 lbs | John Dodson |
| Bantamweight | 135 lbs | Jamel Herring |
| Featherweight | 145 lbs | Kai Stewart |
| Lightweight | 155 lbs | Ben Bonner |
| Welterweight | 165 lbs | Dustin Pague |
| Middleweight | 175 lbs | David Mundell |
| Light Heavyweight | 185 lbs | Lorenzo Hunt |
| Cruiserweight | 205 lbs | Esteban Rodriguez |
| Ironweight | 225 lbs | Lorenzo Hunt |
| Heavyweight | Over 225 lbs (no upper limit) | Andrei Arlovski |
Women's divisions: Strawweight 115 (Britain Hart), Flyweight 125 (Christine Ferea), Featherweight 145 (Jessica Borga). Thirteen divisions in total since July 2026.
For details, see BKFC weight classes explained.
BKB Weight Classes
| Division | Weight Limit | Champion (2026) |
|---|---|---|
| Flyweight | 126 lbs | Active |
| Bantamweight | 134 lbs | Active |
| Featherweight | 145 lbs | Active |
| Lightweight | 155 lbs | Rico Franco |
| Welterweight | 170 lbs | Liam Sheridan |
| Middleweight | 185 lbs | Jimmy Sweeney |
| Light Heavyweight | 205 lbs | Sean George |
| Heavyweight | Unlimited | Daniel Hughes |
Note: BKB uses slightly different weight limits for some divisions compared to BKFC.
Top Dog FC Weight Classes
| Division | Weight Range | Description |
|---|---|---|
| Light | Under 155 lbs | Lighter fighters |
| Middle | 155-185 lbs | Mid-range division |
| Heavy | 185-220 lbs | Heavier division |
| Super Heavy | 220+ lbs | Unlimited heavyweights |
Top Dog uses a simplified four-division system. Fighters are generally matched within these broad categories.
Power Slap Weight Classes
| Division | Weight Limit | Notes |
|---|---|---|
| Flyweight | 135 lbs | Lightest division |
| Bantamweight | 145 lbs | — |
| Featherweight | 155 lbs | — |
| Lightweight | 170 lbs | — |
| Welterweight | 185 lbs | — |
| Middleweight | 205 lbs | — |
| Light Heavyweight | 230 lbs | — |
| Heavyweight | Unlimited | Heaviest division |
Note: Power Slap weight limits differ from standard boxing/MMA classes. Their "Lightweight" at 170 lbs equals traditional "Welterweight."
Gamebred BKMMA Weight Classes
| Division | Weight Limit | Notes |
|---|---|---|
| Flyweight | 125 lbs | — |
| Bantamweight | 135 lbs | — |
| Featherweight | 145 lbs | — |
| Lightweight | 155 lbs | — |
| Welterweight | 170 lbs | Primary division |
| Middleweight | 185 lbs | — |
| Heavyweight | 265 lbs | — |
Gamebred follows standard MMA weight classes.
Organizations Without Formal Weight Classes
| Organization | Matching Method | Weight Tolerance | Notes |
|---|---|---|---|
| Streetbeefs | Visual/scale matching | ~15-20 lbs | A-Train matches fighters by approximate size |
| Strelka | Visual matching | ~10-20 lbs | No formal weigh-ins |
| KOTS | Approximate matching | ~15 lbs | Informal weight matching |
| Rough N' Rowdy | Approximate matching | ~20 lbs | Very loose weight matching |
| Backyard Squabbles | Visual matching | ~20 lbs | Matched by organizers |
| StreetBeefz UK | Visual/scale matching | ~15 lbs | Follows Streetbeefs model |
| Scrapyard FC | Visual matching | ~20 lbs | No formal divisions |
| East Bay Rats | None | Any | Open weight fights common |
| Holmgang | Approximate | ~20 lbs | Informal matching |
| Mahatch FC | Team-based | Varies | Multi-man format, mixed weights |
Weight Class Name Variations
The same weight can have different names across organizations:
| Standard Name | Weight | Also Called |
|---|---|---|
| Strawweight | 115 lbs | Mini Flyweight, Minimum Weight |
| Flyweight | 125 lbs | Junior Bantamweight |
| Bantamweight | 135 lbs | Super Flyweight (in some systems) |
| Featherweight | 145 lbs | Junior Lightweight |
| Lightweight | 155 lbs | — |
| Super Lightweight | 165 lbs | Junior Welterweight (BKFC calls its 165-lb division Welterweight) |
| Welterweight | 170 lbs | — |
| Super Welterweight | 175 lbs | Junior Middleweight |
| Middleweight | 185 lbs | — |
| Super Middleweight | 195 lbs | — |
| Light Heavyweight | 205 lbs | — |
| Cruiserweight | 225 lbs | Bridgerweight (boxing) |
| Heavyweight | 265 lbs (MMA cap) | Unlimited (boxing/BK) |
Women's Weight Classes
| Division | Limit | BKFC | BKB | Gamebred | RNR | Power Slap |
|---|---|---|---|---|---|---|
| Strawweight | 115 lbs | Yes | No | Yes | No | No |
| Flyweight | 125 lbs | Yes | Yes | Yes | No | No |
| Bantamweight | 135 lbs | No | Yes | No | Yes | No |
| Featherweight | 145 lbs | Yes | No | No | Yes | No |
Women's divisions are limited across underground organizations. BKFC has the most developed women's roster. See can women fight underground.
Catchweight Fights
Many underground fights happen at catchweights, where both fighters agree to a non-standard weight. Common scenarios:
| Scenario | Example | Common In |
|---|---|---|
| Between divisions | 163 lbs (between LW and WW) | BKFC, BKB |
| One fighter can't make weight | Agreed upon day-of | All organizations |
| Open weight challenge | No weight limit | Strelka, KOTS, East Bay Rats |
| Short-notice replacement | Closest available fighter | All organizations |
Weight Cutting in Underground Fighting
| Organization | Weight Cut Culture | Weigh-In Timing | Rehydration Rules |
|---|---|---|---|
| BKFC | Moderate | Day before | Standard (no IV) |
| BKB | Moderate | Day before | Standard |
| Top Dog FC | Minimal | Day of | None |
| Power Slap | Moderate | Day before | Standard |
| Gamebred BKMMA | Moderate | Day before | Standard |
| Streetbeefs | None | Day of (if any) | N/A |
| KOTS | None | No formal weigh-in | N/A |
| Strelka | None | No formal weigh-in | N/A |
For safe weight management, see how to cut weight for an underground fight and weight cutting dangers.