This is someone else's post from a thread that I started.
Most guys will cut between 10-20 pounds (safely) by rehydrating before their fight. Surprisingly though it actually seems as if fighters in smaller weight classes cut more weight, as I've read that Dominick Cruz, Aldo and Renan Barao all weigh about 160 on fight night.
Just a round-about estimate by weight class with some outliers mentioned:
205 - 220lbs (Thiago Silva cuts from 230)
185 - 200lbs (I'm honestly pretty sure I read that Vitor cuts from above 205 somewhere)
170 - 185-190lbs (the heaviest GSP ever weighed in the cage was 190 but he's usually more in the mid 180s)
155 - 170-180lbs (Gleison Tibau cuts from 190!!!... and somehow has fairly good cardio too!)
145 - 160ish (Erik Koch says he's 170 on fight night)
135 - 150
125 - 135-140 (seems like this division has more naturally framed fighters as many of 'em are about 5'4", even Scotty Jorgensen who's dropping down in December but has otherwise been a bantamweight his whole career)
Of course I can't really verify those average numbers, but that should give you a reasonable idea. I've never fought or tried to make weight before, but I do wanna try and become an amateur boxer and MMA fighter eventually, and for MMA at least I often thought I'd want to compete at LHW since I'm 6'0" and while quite overweight, could see myself filling out 200-ish lbs with muscle once I actually commit to conditioning training; however I realized that so many guys in that division are usually more like 6'2"-6'3" and cut to make 205, which makes me think perhaps welterweight would be the best fit, as I wanna fight guys my own size (in terms of frame) without cutting much (if any) weight. So, just try to keep stuff like that in mind when thinking about where you'd fit in.
You'd certainly have a bit more headroom if you were down to play the weight cuttin' game though. The most extreme example of this would probably be Anthony Johnson, who is a HW now but tried (keyword: tried) making 170 for quite a while. But I just don't believe in trying to create a size advantage that wouldn't normally be there, myself.
