TEXT: Fixed Hit Points  
  Through the use of these optional, fixed hit point rules, characters would have more hit points (hp) at first but have slightly less hit points at 
  higher levels.  In additional hit point variation would be eliminated for characters and creatures hit point would no longer be rolled. Instead, 
  hit points for player characters and NPCs would be based on their constitution score (CON), class, and level while hit points for creatures 
  would be based on their size, hit dice (HD) and hit die bonus. 
   
  1]  Starting hit points (hp) for player characters and NPCs equal that character’s constitution (CON) score plus a fixed hit point bonus 
   
  based on the hit die type for that character’s chosen class:  
  • 
  d4 = 1 hp 
  • 
  d6 = 2 hp 
  • 
  d8 = 3 hp 
  • 
  d10 = 4 hp 
  • 
  d12 = 5 hp 
   
  2]  After 1st level all characters would get this fixed hit point bonus whenever they advance in level. No CON bonus is added to these, 
   
  fixed, hit points. 
   
  3]  Creatures have a base of 10 hit points.  Large creatures double their base hit points, starting with 20 hit points. Small creatures halve 
   
  their base hit points, starting with 5 hit points.  Each hit die (HD) adds 3 hit points to the base hit points.  Hit die bonuses (e.g. an 8+3 HD 
   
  creature has a +3 hit die bonus) are added to each hit die.  Fractional hit points are rounded up. 
   
  4] 
  NPC humans and demihumans would gain starting hit points just as player characters do.  
   
   
   
  Examples 
  The hit point totals would work out as follows: 
   
  1] 
  Sam the magic-user: A level 1 magic-user with a 10 constitution would have 11 hp.  By level 10 he’d have 20 hp. By level 20 he’d have 
   
  30 hp.  
   
  2]  Bob the fighter:  A level 1 fighter with a 16 CON would have 20 hp. By level 10 he’d have 56 hp. By level 20 he’d have 96 hp. 
   
  3] 
  Shecky the Vampire:  An 8+3 HD vampire would have 58 hp.   
   
  4] 
  Mongo the hill giant:  A 12+2 HD hill giant would have 80 hp. 
   
  5]  Kurble the kobold: A ½ HD kobold would have 7 hp. 
   
  
SOURCE: textdata/thevault/Dungeons & Dragons [multi]/AD&D 3e/AD&D 3e Sheets & Supplements/AD&D 3e Optional Rule Fixed Hitpoints.pdf