OP picrel is a glorified BMI chart. I personally have been saying that should be the standard for these classifications anyway. Before it's been generally accepted that anyone over 250 or so is a BBW, and SSBBW starts at around 350.
If we had a girl at 5'4" on this chart, they'd be a BBW at 200 (which I'm amenable to that being the start) and an SSBBW at 375, which is a feat but attainable.
If we went with BMI and stuck to round numbers, a 35-65-95 rule would work fine. At those weights, that same girl would be 35 and 64 respectively. I don't think anyone would deny that she'd look huge at that size and nitpick her status.
>>28891I take issue with the line for USSBBW here and on the chart. You're lowballing - USSBBW isn't meant to be a somewhat attainable for most of the fatties we see posted online. From what I've seen the threshold is 600lbs, but we've primarily seen that from taller girls and someone like Jackie (currently at 570 or so) is definitely Ultra-sized at 5'2".
Using the same girl from before, she'd have to be 675lbs to be USSBBW, which is a staggering 115 BMI. Even if you knocked off 100lbs she'd still be almost triple digits. For 95 BMI, a 5'4" girl would need to be 555lbs, which is still staggering, rare, and a sight to behold. Short of the typical 600lbs threshold but more forgiving to shorter girls. Maybe 35-65-100 (585lbs)?
Either way, the USSBBW line on this chart is absolutely laughable. You'd be confined to just Adeline and FatMissT being the only USSBBWs in the game if that were the case, and though they'd definitely earn that title, there's plenty who have reached that level of "Fuck I loved her stuff but she's gotten way too fat for me" you see too often on this board.