From version five of Upper_Krust's paper of the same name.
/Appendix Two: Encountering Encounter Levels
/Appendix Three: Design Parameters
Challenge Ratings (CRs) are a measurement of power. There are two general principles regarding CR: firstly that it signifies a moderately challenging encounter for a party of 4–5 characters of the same power…
- e.g. CR 15 suggests the opponent would be a moderate challenge for a party of four (or five) 15th-level characters.
…secondly, that CR parallels character level.
- e.g. A 10th-level character is CR 10 (at least before Ability Scores).
To determine CR, what was needed was a list of all the relevant factors involved; and our best estimation of the effect they have on CR. These factors are outlined below.
- How do factors work?
To determine a monster's Challenge Rating:
- Golden Rule
Class Levels or Hit Dice should always comprise at least half of the creature's total CR. When they don't, halve all excess CR beyond double the creature's CR modifier for Character Levels and Hit Dice.
- e.g. Planetar = Factor Total 39.598
- 14 Outsider Hit Dice Factor = 9.8
- Halve any excess CR beyond 19.6 (2 × HD Factor)
- 39.598 − 19.6 = 19.998
- 19.998/2 = 9.999
- 19.6 + 9.999 = CR 29.599
Table: Fractional Challenge Ratings
| Result |
CR |
Encounter Level
|
| 5 |
5 |
10
|
| 4 |
4 |
9
|
| 3.5 |
3.5 |
8
|
| 3 |
3 |
7
|
| 2.5 |
2.5 |
6
|
| 2 |
2 |
5
|
| 1.75 |
1.75 |
4
|
| 1.5 |
1.5 |
3
|
| 1.25 |
1.25 |
2
|
| 1 |
1 |
1
|
| 0.5 |
2⁄3 |
0
|
| 0 |
1⁄2 |
−1
|
| −0.5 |
1⁄3 |
−2
|
| −1 |
1⁄4 |
−3
|
| −1.5 |
1⁄6 |
−4
|
| −2 |
1⁄8 |
−5
|
| −2.5 |
1⁄12 |
−6
|
| −3 |
1⁄16 |
−7
|
- e.g. Troglodyte: 2.83 (rounds to 2.5) = CR 2.5
- Orc: 0.925 (rounds to 0.5) = CR 2⁄3
- Zombie Human: −0.834 (rounds to −1) = CR 1⁄4
- Lizard: −2.305 (rounds to −2.5) = CR 1⁄12
- List of factors
- Character Levels (Prestige Classes and NPC Classes)
- Templates
- Size
- Traits (Type/Subtype/Race)
- Hit Dice
- Speed
- Armor Class
- Full Attack
- Special Abilities/Qualities
- Ability Scores
- Skills
- Feats
- Equipment
Character Levels[edit]
Class levels
| CR |
Class
|
| +0.8/level |
PC classes, including prestige classes
|
| +0.7/level |
Warrior
|
| +0.65/level |
Aristocrat, expert
|
| +0.6/level |
Adept
|
| +0.45/level |
Commoner
|
Templates[edit]
Example: Half-Dragon = CR +4.25
| Ability Scores (+14) |
CR +1.4
|
| Breath Weapon |
CR +0.15
|
| Dragon Type Traits |
CR +0.5
|
| Energy Immunity (Variable) |
CR +1
|
| Flight (Average) |
CR +0.6
|
| Improved Hit Die Type |
CR +0.2
|
| Natural Armor (+4) |
CR +0.4
|
Challenge Rating Modifier for Size
| Size |
CR |
CR plus Ability Score mods
|
| Fine |
+1.35 |
+0.55
|
| Diminutive |
+0.3 |
−0.3
|
| Tiny |
+0.05 |
−0.55
|
| Small |
— |
−0.4
|
| Medium |
— |
—
|
| Large |
+0.4 |
+1.4
|
| Huge |
+0.7 |
+2.9
|
| Gargantuan |
+1 |
+4.4
|
| Colossal |
+1 |
+5.6
|
| Colossal+ |
+2.1 |
+7.9
|
Size breakdown:
| Ability Score Bonus/Penalty |
±0.1/point
|
| Armor Class Bonus/Penalty |
±0.1/point
|
| Attack Bonus/Penalty |
±0.1/point
|
| Movement (base) |
±0.01/foot difference from 30
|
| Reach |
±0.04/foot difference from 5
|
| Space |
∓0.1/size category difference
|
| Weight Allowance Modifier |
±0.1/size category difference
|
Traits (Type/Subtype/Race)[edit]
Aberration Type Traits = CR +0.2
| Darkvision |
+0.2
|
Animal Type Traits = CR −0.75
| Intelligence 1 or 2 |
−0.85
|
| Low Light Vision |
+0.1
|
Construct (Mindless) Type Traits = CR +0.7
| No Constitution |
+1.9
|
| Darkvision |
+0.2
|
| Hit Point Bonus |
+0.2
|
| No Intelligence |
−0.7
|
| Low-Light Vision |
+0.1
|
| No Natural Healing |
−1
|
Intelligent constructs get an additional +0.7
Dragon Type Traits = CR +0.5
| Darkvision |
+0.2
|
| Low-Light Vision |
+0.1
|
| Paralysis/Sleep Immunity |
+0.2
|
Elemental Type Traits = CR +1.2
| Can't be raised, etc. |
−0.2
|
| Can't be flanked |
+0.2
|
| Critical Hit Immunity |
+0.5
|
| Darkvision |
+0.2
|
| Poison Immunity |
+0.2
|
| Sleep/Paralysis/Stun Immunity |
+0.3
|
Fey Type Traits = CR +0.1
| Low-Light Vision |
+0.1
|
Giant Type Traits = CR +0.2
| Darkvision |
+0.2
|
Magical Beast Type Traits = CR +0.2
| Darkvision |
+0.2
|
Monstrous Humanoid Type Traits = CR +0.2
| Darkvision |
+0.2
|
Ooze Traits = CR +1.9
| Blindsight |
+1
|
| Critical Hit Immunity |
+0.5
|
| Can't be flanked |
+0.2
|
| Hit Point Bonus |
+0.2
|
| No Intelligence |
−0.7
|
| Poison Immunity |
+0.2
|
| Polymorph Immunity |
+0.2
|
| Sleep/Paralysis/Stun Immunity |
+0.2
|
Intelligent oozes get an additional +0.7
Outsider Type Traits = —
| Can't be raised, etc. |
−0.2
|
| Darkvision |
+0.2
|
Plant (Mindless) Type Traits = +0.6
| Critical Hit Immunity |
+0.5
|
| No Intelligence |
−0.7
|
| Low Light Vision |
+0.1
|
| Poison Immunity |
+0.2
|
| Polymorph Immunity |
+0.2
|
| Sleep/Paralysis/Stun Immunity |
+0.3
|
Intelligent plants get an additional +0.7
Undead (Mindless) Type Traits = +0.2
| Can be turned, etc. |
−1.5
|
| No Constitution |
+1.9
|
| Darkvision |
+0.2
|
| No Intelligence |
+0.2
|
|
+0.2
|
More later.
Aberration Type Traits = +0.2
| Darkvision |
+0.2
|
Aberration Type Traits = +0.2
| Darkvision |
+0.2
|
Aberration Type Traits = +0.2
| Darkvision |
+0.2
|
Aberration Type Traits = +0.2
| Darkvision |
+0.2
|
Aberration Type Traits = +0.2
| Darkvision |
+0.2
|
Effective Character (ECL)[edit]
Revised Challenge Ratings[edit]
Substituting Core Rules[edit]