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Track your camp day by day
After you calculate, adults can save the camp on their phone and log a morning weight each day. Every entry is checked against the same model the calculator uses: the weight still to lose, the days left, and the final water cut that pace would leave for fight week. If that water cut moves above the professional range, the tracker says so on the day, while there is still time to change the plan.
The tracker keeps everything on your own phone. There is no account, nothing is sent to this site, and one button deletes the camp.
What this calculator does
It takes three things and returns a range: your current weight, the weight you are trying to make, and the weigh-in format you compete under. The format is doing more work than most people expect, because the time between the scale and the first bout decides how much of what you remove can be replaced.
The figures behind it are not invented. The 2025 ISSN position stand on combat sports puts suitable acute losses at about 4.4 percent of body mass in the final 24 hours before the weigh-in, 5.7 percent in the final 48 and 6.7 percent in the final 72, and it keeps sauna, hot baths and wraps to about 2 to 4 percent within the last 24 hours. The calculator's green and amber zones sit inside those figures. For a same-day weigh-in it halves them, because nothing removed gets meaningfully replaced before you compete.
How these reference figures played out in six public UFC cuts: weight cut case studies.
What it cannot tell you
Three things, and they matter.
Whether you are in the right division. The calculator answers whether a cut is survivable, not whether it should be happening. A fighter who reaches the ceiling every camp is being told something about his weight class rather than about his discipline.
What your own regain looks like. The ranges here are population figures. Your number depends on your history, your format and how the previous cuts went, and establishing it requires weighing yourself at the right moments rather than estimating.
Anything about your health. This is an arithmetic tool. It does not know about your medical history, your medication or what happened during your last cut, and it is not a substitute for somebody who does.
Common questions
Can I track my weight cut day by day?
Yes. After you calculate, tap Start tracking to save the camp on your phone, then log your morning weight each day. Each entry is checked against the same model, and the tracker shows the final water cut your pace would leave. It is for adults only, and nothing is sent to this site.
How accurate is a weight cut calculator?
It gives a population range, not a personal prediction. The percentages behind it come from published research on combat sport athletes. Your own figure depends on your history, your sweat rate and how the previous cuts went. Treat the output as a ceiling to stay inside, not a target to hit.
How much weight can I safely cut before a weigh-in?
The 2025 ISSN position stand puts suitable acute losses at about 4.4 percent of body mass in the final 24 hours before the weigh-in, 5.7 percent in the final 48 and 6.7 percent in the final 72. A same-day weigh-in leaves far less room, because little of what is removed can be replaced before the bout.
Why does the weigh-in format change the answer?
Because the gap between the scale and the first bout decides how much of what you removed can be replaced. A morning weigh-in the day before leaves around 30 hours. An afternoon weigh-in leaves around 24. A same-day weigh-in leaves almost nothing, and the plan has to be built differently from the start.
Does the calculator tell me which weight class to fight at?
No, and that is the more important question. The calculator answers whether a cut is survivable, not whether it should be happening.
Is the weight cut calculator free?
Yes. No sign-up, no payment, seven languages.
Where to go next
If the number comes back higher than you expected, the reading that follows is choosing a weight class, because that decision governs everything downstream.
If you want the reasoning behind the percentages, it is in how much you can actually lose in a week. The rules that apply at your own weigh-in, sport by sport, are in the weigh-in rules reference. And what to do in the hours after the scale, which is where most fights are quietly lost, is in rehydration after the weigh-in.
The calculator is free and stays free. It exists because the arithmetic is the part fighters most often get wrong, and it is the part that takes 2 minutes to get right.