About

A miscalculated ability modifier cascades through every roll at the table. Wrong AC means your character absorbs hits they should dodge. Incorrect proficiency bonuses compound across dozens of skill checks per session. This generator computes ability modifiers using the standard formula score − 102 (rounded down), derives hit points from class-specific hit dice d plus CON modifier per level, and cross-references proficiency bonuses against a level-indexed lookup table. It supports three generation methods: 4d6-drop-lowest (statistical mean ≈ 12.24), point-buy with the SRD cost curve, and the standard array [15, 14, 13, 12, 10, 8].

The tool assumes SRD 5.1 baseline rules. Homebrew modifiers, feats altering score caps beyond 20, and multiclass proficiency interactions are not automatically resolved. Validate edge cases like negative CON modifiers reducing hit dice rolls below 1 (the SRD enforces a minimum of 1 HP per level). Pro tip: always finalize your race selection before assigning point-buy scores, as racial bonuses shift optimal allocation thresholds.

Formulas

Ability modifier derivation from raw score:

modifier = floor(score − 102)

Hit points at level 1 and subsequent levels:

HP₁ = hitDie_max + CON_mod

HP_n = HP₁ + n∑i=2 (roll(hitDie) + CON_mod)

Minimum HP gained per level is 1, regardless of negative CON modifier. Armor Class without armor:

AC = 10 + DEX_mod

Proficiency bonus by level:

PB = ceil(level4) + 1

Skill check modifier when proficient:

skillMod = abilityMod + PB

The 4d6-drop-lowest method: roll four six-sided dice, discard the lowest, sum the remaining three. Expected value per score ≈ 12.24, standard deviation ≈ 2.85.

Where score = raw ability score (3 - 20), hitDie = class-specific die (d6 to d12), CON_mod = Constitution modifier, PB = proficiency bonus, level = character level (1 - 20).

Reference Data

Class	Hit Die	Primary Ability	Saving Throws	Armor Proficiencies	Starting HP
Barbarian	d12	Strength	STR, CON	Light, Medium, Shields	12 + CON mod
Bard	d8	Charisma	DEX, CHA	Light	8 + CON mod
Cleric	d8	Wisdom	WIS, CHA	Light, Medium, Shields	8 + CON mod
Druid	d8	Wisdom	INT, WIS	Light, Medium, Shields	8 + CON mod
Fighter	d10	STR or DEX	STR, CON	All, Shields	10 + CON mod
Monk	d8	DEX & WIS	STR, DEX	None	8 + CON mod
Paladin	d10	STR & CHA	WIS, CHA	All, Shields	10 + CON mod
Ranger	d10	DEX & WIS	STR, DEX	Light, Medium, Shields	10 + CON mod
Rogue	d8	Dexterity	DEX, INT	Light	8 + CON mod
Sorcerer	d6	Charisma	CON, CHA	None	6 + CON mod
Warlock	d8	Charisma	WIS, CHA	Light	8 + CON mod
Wizard	d6	Intelligence	INT, WIS	None	6 + CON mod

Frequently Asked Questions

Rolling four dice and discarding the lowest creates a right-skewed distribution. The expected value shifts from 10.5 (3d6 flat) to approximately 12.24 because the discard disproportionately removes low results. The probability of rolling below 8 drops from roughly 25.9% to about 5.3%.

The standard SRD point-buy system constrains all scores to the range [8, 15] with a budget of 27 points. Scores of 14 and 15 cost 2 points per increment instead of 1, reflecting diminishing returns. Racial bonuses are applied after point-buy and may push a score above 15, but the base purchase cannot exceed that ceiling.

Per SRD rules, a character gains a minimum of 1 hit point per level regardless of modifiers. If a Wizard (d6) with a −2 CON modifier rolls a 1 on the hit die, the raw result would be −1, but it is clamped to 1. This tool enforces that floor automatically.

Monks use Unarmored Defense: AC = 10 + DEX_mod + WIS_mod. Barbarians use AC = 10 + DEX_mod + CON_mod. These formulas replace the standard 10 + DEX_mod and do not stack with worn armor. A shield (+2) can be added to either.

Yes. The formula PB = ceil(level ÷ 4) + 1 produces +2 at levels 1 - 4, +3 at 5 - 8, +4 at 9 - 12, +5 at 13 - 16, and +6 at 17 - 20. This matches the SRD table exactly.

Under standard SRD rules, ability scores cannot exceed 20 through racial bonuses or ability score improvements. This tool caps all final scores at 20. Some optional rules or feats allow scores up to 30, but those require manual override beyond this generator's scope.