MMA Weight Cut Calculator
Enter your walk-around weight, the division you're eyeing, and how many weeks you have. The calculator splits your cut into a sustainable diet phase and a fight-week water cut — and tells you honestly whether the math is safe, sketchy, or a hospital trip.
How the math works
The calculator uses two commonly cited guidelines. First, gradual fat loss of roughly 0.5–1% of body weight per week is considered sustainable without torching your training camp — we use 0.75% as the midpoint, and only count usable camp weeks. Whatever the diet phase can't cover is assigned to the fight-week water cut: dropping water weight through fluid manipulation and sweating in the final days before the scale.
The water cut is where the risk lives, so that's what gets graded. As a share of your body weight: under 5% is the zone most performance staff consider manageable, 5–8% is where performance and kidney markers measurably suffer, and beyond 8% is the territory where fights get cancelled and fighters end up on IV drips or worse. For the full science — glycogen, sodium, rehydration windows — read our guide on how weight cuts work.
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Frequently Asked Questions
How much weight can an MMA fighter safely cut?
A common guideline is that gradual diet loss of around 0.5 to 1 percent of body weight per week is sustainable, and a fight-week water cut under about 5 percent of body weight is the lower-risk zone. Cuts above roughly 8 percent of body weight in water are widely considered dangerous.
How does this weight cut calculator work?
It splits your total cut into two phases: a gradual diet phase based on your weeks of lead time, and a fight-week water cut for whatever remains. It then grades the water cut as a percentage of your body weight against commonly cited safety bands.
Is this calculator medical advice?
No. It is an educational estimate based on commonly cited guidelines. Real weight cuts affect kidney function, heart strain and brain safety, and should only be done under qualified medical and nutrition supervision.
This tool is for education and entertainment. It is not medical, nutrition, or training advice, and it doesn't know your body. If you're actually cutting weight for competition, work with a qualified physician and combat-sports nutritionist — and listen to them, not a web page.