Weigh-in rules by sport: the reference table

Every plan for making weight starts with four answers: when you weigh in, what is measured, what tolerance exists afterwards, and what happens if you miss. This page holds those answers for eight formats in one table, with the detail underneath it.

The table

Professional boxing

Two authorities operate at once, and four separate instruments can constrain your weight. The sanctioning body has its rules, the commission has its own, the contract may add a clause, and the promotion may add a check.

The mechanics of the test itself, and why the same threshold appears in two sports doing opposite jobs, is in hydration testing.

• IBF second-day weigh-in. On the morning of the fight, a boxer may not exceed the division limit by more than 10 lb, about 4.5 kg. This is the only mandatory second weigh-in of its kind in major professional boxing, and it is waived at heavyweight and in unification bouts.
• WBC camp checks. Weight monitoring at set points during camp rather than a second scale on fight day: at 30 days out no more than 10 percent above the limit, at 14 days no more than 5 percent, and at 7 days no more than 3 percent, for non-heavyweights. Non-compliance can bring fines or other sanctions.
• Contract clauses. Negotiated between the parties and enforceable as a term of the bout agreement. Four different things get called a "rehydration clause", which is why the word alone tells you nothing.
• Commission rules. Vary by jurisdiction.

The full comparison is in rehydration rules: what each organisation actually enforces, and what happens when a clause is breached is in failing a rehydration clause.

MMA

Weigh-ins are typically held early on the morning of the day before, which gives roughly 30 hours before the fight. No sanctioning body caps how much weight goes back on, though some commissions record it.

The UFC's divisions, the one-pound allowance and what a miss costs are laid out in UFC weight classes.

That absence is the defining feature of the sport as a weight-making problem: nothing external limits the cut, so everything depends on the athlete and the team. The detail is on the MMA page.

Taekwondo (WT)

Structurally this looks like judo: a general weigh-in the day before, and a random check at the venue on the morning of competition. Two differences matter.

The first is that there is no tolerance at the morning check. Judo allows 5 percent above the category limit. Taekwondo allows nothing, and failure to appear for the random weigh-in is a disqualification rather than a warning. The random check happens once. There is no second attempt at it, although the general weigh-in the day before does allow a further try within its 2-hour window.

The second is the one that makes this sport different from everything else on this page.

Competitors are weighed without the dobok. A competitor marginally over may be permitted to strip further, subject to the officials and to being directed somewhere private.

The practical consequence for planning is that the target is a band rather than a maximum, and the band is narrow.

A cut planned to land somewhere under the limit, which is normal practice everywhere else, is the wrong plan here.

Judo (IJF)

The official weigh-in is the day before. On competition day there is a random weigh-in at which a selected athlete may not exceed the upper limit of the category by more than 5 percent.

Because the cap is a percentage, the room it gives you differs by category. This is the calculation most judoka have never done.

Published tables sometimes round these differently. Plan below the figure rather than at it. The heavyweight categories have no upper limit, so the arithmetic does not apply to them, and the random check is an IJF arrangement that may be run differently or not at all at national events.

The refill, golden score and the rest of the day are in the Judo Competition Guide.

Wrestling (UWW)

The 2-day competition format took effect on 1 January 2018. Medical control comes first, then the weigh-in.

The day-two tolerance is where most coaching advice is wrong.

• Olympic Games, World Championships, Continental Championships: zero tolerance.
• Ranking Series, World Cup and certain international tournaments: 2 kg.

At the 2024 Olympics an athlete made day one, won 3 bouts, and was found about 100 grams over the following morning. No tolerance applied and the rule was enforced.

Both the format and the tolerance schedule are UWW rules; school and college competition runs different arrangements.

The 2-day format written out in full, including the evening between the scales, is the Wrestling Competition Guide.

Amateur boxing

Two separate procedures, and confusing them is a common and expensive error.

• The general weigh-in or entries check, before the tournament begins. Both the minimum and the maximum for the category are controlled, and the weight registered there fixes your category for the whole event.
• The daily weigh-in, on the morning of each day you box. Only the maximum is controlled. Over it, you do not box.

That is the international arrangement. Purely national tournaments are often looser, and some fix the category differently or apply their own tolerances.

The consequence for a competitor is set out on the page for judo, wrestling and amateur boxing.

Holding a weight across a tournament week is the subject of the Amateur Boxing Guide.

BJJ (IBJJF)

You weigh in shortly before your first match, wearing the gi you will compete in, with one attempt and no tolerance.

There is no recovery window because there is no gap between the scale and the mat.

The gi itself counts, which makes the uniform part of the arithmetic rather than an afterthought. Some other organisations differ: NAGA, for instance, allows a small allowance, commonly 1 lb, and more flexibility on changing or merging divisions.

The detail is on the BJJ page.

Kit weight by weave and size, and the timeline that follows from it, are in the BJJ Competition Guide.

Muay Thai and kickboxing

Neither sport has a single governing body, and both contain two opposite systems.

• Thai stadium circuit. Lumpinee publishes a same-day weigh-in between 08:00 and 12:00, a minimum of 100 lb, a minimum age of 15 for professional bouts, and a maximum weight difference of 5 lb between opponents. Other stadiums and promoters differ, and there is no central rulebook.
• Amateur kickboxing under WAKO. Weigh-in on the morning of competition, and on each morning of a multi-day tournament.
• Professional kickboxing. Typically 24 to 36 hours before. Missing weight commonly costs a share of the purse, reported between 15 and 40 percent and most often 20 to 30, and in a title bout it costs eligibility for the belt. These figures are contractual and set by the promoter rather than fixed by any single rule, so the number that applies to you is the one in your own agreement.
• ONE Championship, across its Muay Thai and kickboxing divisions, uses the hydration-tested system described below.

More on each: Muay Thai and kickboxing.

Both are written out format by format in the Muay Thai Competition Guide and the Kickboxing Competition Guide.

Hydration-tested promotions

A different solution to the same problem. Rather than capping the refill afterwards, dehydration is designed out beforehand.

ONE Championship weighs athletes and tests hydration in the days before the event, requiring urine specific gravity at or below 1.025, and matches on walking weight rather than on a dried-out figure. Failing either part means not competing at that weight. There is a window of about 3 hours to try again, after which a catchweight can be negotiated provided both athletes sit within 105 percent of each other's weight.

Missing weight there commonly costs a percentage of the purse, usually reported at 20 to 30 percent, paid to the opponent.

What happens when you miss

The table above tells you when you stand on the scale. This section tells you what follows if the number is wrong, which is the question people actually arrive with.

Professional boxing

Miss the contracted weight at the official weigh-in and, in a title bout, you are typically given up to 2 hours to make it. In a non-title bout under some commissions you get one attempt on the scale, with the exception that a fighter over the weight may remove undergarments and try again.

If you still miss, the bout usually proceeds. What changes is the money and the belt. A challenger who misses cannot win the title. A champion who misses is stripped on the scale, and the belt can only be won by the opponent.

A share of the purse commonly moves across, and the percentage is a contract term rather than a rule.

The same guidelines set out the routes back for a boxer who comes in heavy: losing all but 2 pounds of the excess at least 12 hours before the event and the final 2 pounds at least 6 hours before, or losing up to 2 pounds at least 6 hours before and renegotiating the contract.

There is also a safety limit on how much may be shed inside that window.

Where weigh-ins happen less than 12 hours before the event, no excess is permitted at all.

MMA

Non-title bouts carry a 1-pound allowance. A lightweight fight contracted at 155 is made at 156.0 or under. Title bouts carry none: the limit is exact.

Some jurisdictions outside the United States work to 1.5 pounds or 0.5.

Miss it and you are usually given a further window, commonly 1 to 2 hours depending on the commission, to try again. Championship bouts have attracted longer allowances in some states.

Fail the second attempt and the bout typically becomes a catchweight, contingent on the opponent accepting it and the commission approving. The fighter who missed commonly forfeits a percentage of the purse, frequently reported in the range of 20 to 30 percent.

A champion who misses is stripped on the scale and cannot win the belt back that night. Only the opponent remains eligible.

What you wear on the scale

This decides outcomes more often than people expect, and it differs by sport.

The gi and the singlet are the ones that catch people, because the garment is inside the limit rather than outside it. A wrestler cutting to the gram and a jiu-jitsu competitor who changed gi between events are both losing weight they did not budget for.

Taekwondo's categories and its random 5 percent check are set out on the taekwondo weight classes page.

One set of rules this page does not cover

Powerlifting has the same split, a 2-hour weigh-in in the IPF system against a day-before weigh-in in the USPA and most other federations, and its classes and weigh-in formats are on their own page.

Medical suspensions run on a separate track from anything above. A knockout carries a minimum of 60 days out, a technical knockout from head blows 30, and any bout at all a mandatory 7-day rest. Those periods usually carry two dates rather than one: no competition, and a shorter no-contact window inside it that governs sparring.

They are set by the commission rather than the sanctioning body, and the figures are in what the rules already require after head trauma.

What this table cannot tell you

Three things, and they matter enough to say plainly.

• Your specific event. National and regional competitions frequently differ from the international rules above, sometimes substantially. Ask the organiser rather than assuming.
• The date. Rules change. This page carries a date at the top for exactly that reason, and anything you read here should be confirmed against the current rulebook before you agree a weight.
• Your contract. In professional sport a bout agreement can add terms that no rulebook contains, and those are negotiated rather than fixed. The list of terms worth checking is in failing a rehydration clause.

Corrections welcome

If something here is out of date or wrong for your organisation, tell me and I will check it and change it. The contact address is at the bottom of the page.

A reference is only worth keeping if it is maintained, and the reason so much bad advice circulates in this sport is that nobody bothers to update the good advice.

This table is the frame. What your particular bout is actually held to is written in the contract, and the four terms that decide it are in the bout agreement.

Two rows deserve reading twice. Wrestling asks you to make weight on two separate mornings, and judo caps your refill by percentage: wrestling and judo.