What Is the Lightest Boxing Weight Class?
The lightest men's pro boxing class is minimumweight at 105 lb. Women's atomweight is 102 lb. Compare names, limits and amateur categories.
The lightest weight class in men’s professional boxing is minimumweight, also called strawweight or mini flyweight, with a limit of 105 pounds (about 47.63 kg). The WBC lists strawweight at 105 lb; the WBO calls its 105 lb division mini flyweight. (WBC division list, WBO championship regulations, Section 3)
Women’s professional boxing goes lighter: atomweight has a 102-pound limit (about 46.27 kg). It is the lowest division in the WBC’s July 2026 women’s ratings. So “105 pounds” is the answer for men’s professional boxing—not for every category of boxing. (WBC women’s ratings, July 2026) Recognition and naming can differ by sanctioning body; our women’s weight-class guide compares those systems.
The smallest professional divisions
These are upper weight limits, not weights every boxer must hit exactly. Kilogram figures are rounded conversions.
| Division | Upper limit | Where it fits |
|---|---|---|
| Atomweight | 102 lb / 46.27 kg | Women’s professional division below minimumweight |
| Minimumweight / strawweight / mini flyweight | 105 lb / 47.63 kg | Lightest men’s professional division; also contested by women |
| Light flyweight / junior flyweight | 108 lb / 48.99 kg | Next division above minimumweight |
| Flyweight | 112 lb / 50.80 kg | Next division above light flyweight |
Sources: WBC women’s ratings and WBO weight categories.
The names can make the bottom of a fight card look more complicated than it is. Minimumweight, strawweight and mini flyweight describe the same 105-pound class, not three separate divisions. Light flyweight is different: its ceiling is three pounds higher. BoxRec’s division reference lists minimumweight and mini flyweight together.
“Lightweight” is not shorthand for the lightest class, either. It is a specific professional division with a 135-pound limit—30 pounds above minimumweight. (WBO regulations, Section 3) For the full sequence, see boxing weight divisions in order.
Amateur boxing uses different categories
Do not apply the professional 105-pound answer automatically to an amateur tournament. Under World Boxing’s elite categories effective from January 1, 2025, the smallest men’s class is flyweight, 47–50 kg; the smallest women’s class is light flyweight, 45–48 kg. Those are different categories from professional flyweight and light flyweight despite sharing names. (World Boxing rules, Section 2.2.2)
Age groups and individual competitions matter, too. World Boxing’s November 2024 rules list a smaller 44–46 kg pinweight category for U17 boys and girls. Check the event’s governing rules rather than treating an elite or professional list as universal. (World Boxing rules, Section 2.2.4) Our amateur weight-division guide separates the main systems.
Does the lighter weight change scoring?
There is no separate points scale for minimumweights. The Association of Boxing Commissions’ Unified Boxing Rules specify the 10-point must system without creating a different system for lighter divisions. Weight identifies the division; it is not a scorecard bonus. (ABC Unified Boxing Rules)
To interpret the judges’ numbers, use the 10-point must scoring guide, not the fighters’ weight-class labels.