Keep Highest and Lowest

The kh (keep highest) and kl (keep lowest) modifiers filter which dice contribute to the final result. The number after kh/kl specifies how many dice to keep — it defaults to 1 if omitted (see Implied Defaults).

Syntax

• NdXkhM — Roll N dice, keep the M highest
• NdXklM — Roll N dice, keep the M lowest
• NdXkh — Shorthand for NdXkh1
• NdXkl — Shorthand for NdXkl1

D&D 5e Advantage/Disadvantage

Roll	Notation
Advantage	2d20kh
Disadvantage	2d20kl
Advantage + modifier	2d20kh+5

Call of Cthulhu Bonus/Penalty Dice

Using d% (percentile pair), kh/kl operates on the tens die only, leaving the units die fixed:

Roll	Notation
Standard skill check	d%
One bonus die	2d%kl
Two bonus dice	3d%kl
One penalty die	2d%kh
Two penalty dice	3d%kh

Note: 2d100kl is different — it rolls two independent flat d100s and keeps the lowest complete result. See d% vs d100.

Custom Skill System

The same mechanic powers the custom d[0..5] skill system:

Skill Level	Notation
Unskilled	4d[0..5]
Skill +2	6d[0..5]kh4
Skill -2	6d[0..5]kl4

D&D 5e Ability Scores

4d6kh3 — Roll 4d6, keep the highest 3.

See also: Notation Spec, d% vs d100, Custom Skill System