MMA weight classes: UFC and ONE limits, with amateur rules explained

Correction, 12 September 2026: The previous version presented a UFC-style list as a general MMA standard and included women's featherweight without clarifying its current UFC status. This replacement separates UFC and ONE rules, explains amateur scope and removes unrelated archive statistics and generic weight-cutting instructions. The original publication date, 17 March 2026, is retained.

A division name is only useful when you know the organisation behind it. A lightweight bout in one promotion can use a different weight limit from a lightweight bout in another. The first question is therefore who is staging the fight, followed by the sport, the division and the terms for that particular contest.

This guide compares published professional UFC and ONE categories. It also explains what an amateur competitor needs to check with IMMAF or a national federation. The tables describe competition limits, not recommended body weights or a plan for changing weight.

UFC: division limits and current men's and women's scope

The pound limits below come from UFC's weigh-in guide. The men's and women's column follows the divisions listed in UFC's current rankings on 12 September 2026. Historical records can include divisions that are absent from that current list.

UFC publishes a one-pound allowance for non-title bouts, but no championship allowance. Confirm the official limit and supervising authority's instructions for the actual contest.

ONE: published weight ranges

ONE's chart specifies these ranges, excluding the lower boundary and including the upper one. It does not establish that every category has both men's and women's MMA competition or an active championship.

ONE requires a urine-specific-gravity result of 1.025 or below before the athlete immediately weighs in. Both hydration and contracted weight must be passed. The official protocol covers timing and possible catchweights. Do not apply UFC's allowance to this system.

Three examples that prevent common reading errors

1. The same scale reading can meet one limit and exceed another

A hypothetical UFC lightweight at 155.5 lb meets the published 156 lb non-title limit but exceeds the 155 lb championship limit. This comparison does not decide bout approval or title eligibility.

2. Compare pounds before comparing labels

UFC featherweight has a 145 lb division limit; ONE featherweight extends to 155 lb. Calling both athletes featherweights does not make those limits equal. For a cross-promotion comparison, record the numeric limit and weigh-in process alongside the name. Those details still cannot establish either athlete's actual weight during the fight.

3. A rounded kilogram figure is not a new official threshold

The kg columns are our conversions, rounded to one decimal place. The conversion is 1 lb = 0.45359237 kg, as given in NIST Handbook 44, Appendix C. Thus 155 lb is approximately 70.3068 kg and appears here as 70.3 kg.

Use rounded figures to understand the size of a division. For an official weigh-in, use the event's stated unit, limit, precision and procedure. Converting a displayed rounded number back into pounds can produce a small discrepancy that is only a consequence of rounding.

Amateur MMA: identify the age and competition category first

IMMAF's 2025 rules announcement distinguishes Youth, Junior, Senior and Masters competition. A professional promotion's men's or women's chart is therefore not an amateur entry form. Confirm the event's sex category, age division, weight options, units and weigh-in policy through its current entry pack and your national federation.

There is a specific 2026 change to watch for: IMMAF now uses birth years for youth age divisions, with a Youth A exception requiring athletes to remain under 18 through their competition period. A birthday before or during that period can therefore matter even if a birth year appears on the Youth A list. Read the 2026 age-eligibility notice before registering.

The IMMAF policy directory is a useful starting point, but check dates inside its documents and request the rules for your event. Do not transfer UFC's non-title allowance to an amateur tournament, or assume that an adult limit applies to a youth athlete.

What to check on a fight announcement

• Promotion and discipline: identify MMA specifically when an event also includes other combat sports.
• Division and numeric limit: keep the pounds or kilograms beside the name.
• Category: distinguish men's and women's competition, and professional from amateur age divisions.
• Bout terms: establish whether it is a title contest, a standard divisional bout or an agreed catchweight.
• Official outcome: read the final weigh-in report for a pass, a miss or revised terms. A planned bout is not confirmation that every requirement was met.

If an archive only says “FW”, keep the division unresolved until another reliable record clarifies it. Do not guess a weight class from a fighter's current profile or use an uncertain abbreviation to build division statistics. Names, weights and dates belong together when comparing different eras or organisations.

Method and disclosure: Prepared with AI assistance from the linked official UFC, ONE, IMMAF and NIST sources, checked on 12 September 2026. Tables are a fan reference, with calculated metric equivalents; no personal weight-cutting or medical advice is provided. The event organiser and supervising authority determine the applicable competition rules.