Rules for calculating experience point values for monsters (and NPCs) changed when AD&D moved from 1st to 2nd Edition; in general, rules were simplified for the new edition, and experience values were inflated in general. One reason for this may have been the new lack of emphasis on the older "treasure = X.P." rule, but this was still kept as an optional rule in 2nd Edition, in the end letting players reach higher levels sooner. Higher level monsters show the most X.P. inflation; for example, the Vodyanoi was worth 650+10 X.P./hp (an average of 1,010 XP), but became inflated to 2,000 XP flat (nearly double!).

AD&D 1st Edition Experience Point Values Experience Level or Monster's Hit Dice* Basic X.P. Value (BXPV) X.P. Per Hit Point (XP/HP) Special Ability X.P. Bonus (SAXPB)** Exceptional Ability X.P. Addition (EAXPA)*** up to 1-1 5 1 2 25 1-1 to 1 10 1 4 35 1+1 to 2 20 2 8 45 2+1 to 3 35 3 15 55 3+1 to 4 60 4 25 65 4+1 to 5 90 5 40 75 5+1 to 6 150 6 75 125 6+1 to 7 225 8 125 175 7+1 to 8 375 10 175 275 8+1 to 9 600 12 300 400 9+1 to 10+ 900 14 450 600 11 to 12+ 1300 16 700 850 13 to 14+ 1800 18 950 1200 15 to 16+ 2400 20 1250 1600 17 to 18+ 3000 25 1550 2000 19 to 20+ 4000 30 2100 2500 21 and up 5000 35 2600 3000 *Treat peasants/levies as up to 1-1, men-at-arms as 1-1 to 1, and all levels as the n+1 hit dice category **Typical special abilities: 4 or more attacks per round, missile discharge, armor class 0 or lower, special attacks (blood drain, hug, crush, etc.), special defenses (regeneration, hit only by special and/or magic weapons), high intelligence which actually effects combat, use of minor (basically defensive) spells. ***Typical exceptional abilities: energy level drain, paralysis, poison, major breath weapon, magic resistance, spell use, swallowing whole, weakness, attacks causing maximum damage greater than 24 singly, 30 doubly, 36 trebly, or 42 in all combinations possible in 1 round.

AD&D 2nd Edition Experience Point Values Hit Dice or Level XP Value Less than 1-1 7 1-1 to 1 15 1+1 to 2 35 2+1 to 3 65 3+1 to 4 120 4+1 to 5 175 5+1 to 6 270 6+1 to 7 420 7+1 to 8 650 8+1 to 9 975 9+1 to 10+ 1400 11 to 12+ 2000 13+ 3000+1000 per additional Hit Die over 13 Hit Dice Value Modifiers +1: Armor Class 0 or lower, Blood drain, Causes disease, Flies, Four or more attacks a round, Greater than normal hit points, High Intelligence, Hit only by magical/silver weapons, Immunity to any spell, Immunity to any weapon (including 1/2 damage), Invisible at will, Level 2 or lower spells, Missile weapons, Possesses magical items usable against PCs, Regeneration, Special defense form (unlisted), Special non-magical attack form (unlisted) +2: Breath weapon Level 3 or greater spells, Magic resistance, Multiple attacks causing 30+ points of damage, Paralysis, Poison, Single attack causing 20+ points of damage, Special magical attack form (unlisted), Weakness or fear +3: Energy drain, Petrification