Bones! Notation Reference

Bones! rolls dice using Roll20-compatible notation: the same dice-expression grammar documented in the Roll20 Dice Reference. This page covers the notation you type into a Forms dice button. Roll20's chat-only features (roll queries, roll templates, inline rolls, macros, secret rolls) are not part of the dice notation and do not apply here.

Several modifiers below use a Compare Point (CP): an optional operator (<, =, >) followed by a number. In Roll20 notation >N means "greater than or equal to N" and <N means "less than or equal to N"; if the operator is omitted, = is assumed.

Basic Rolls

• d20 - roll a single d20
• 2d6 - roll two six-sided dice
• 1d8+5 - roll a d8 and add 5
• 3d6-2 - roll three d6 and subtract 2

In NdX, the dice count N must be 0 or more and the sides X must be 1 or more.

Math Operators and Functions

Standard arithmetic with normal order of operations:

• +, -, * (multiply), / (divide)
• % - modulus (remainder): 7%2 is 1
• ** - exponent: 2**3 is 8 (a square root is x**0.5)
• floor(x), ceil(x), round(x), abs(x) - rounding and absolute value
• parentheses to group: (2d6+2)*3

Example: floor(11/2) + 1d6

Precedence, highest to lowest: parentheses, then floor/ceil/round/abs, then **, then * / %, then + -.

Dice Types

Standard Dice

NdX rolls N dice with X sides each: 4d6, 1d100. N must be 0 or more, X must be 1 or more.

Fate / Fudge Dice

NdF rolls N Fate/Fudge dice, each reading -1, 0, or +1 (so 4dF ranges -4 to +4): 4dF, 4dF+1.

Computed Dice

(N+Y)dX or Nd(X+Y) works out the number of dice, or the number of sides, from an expression in parentheses: (2+2)d6, 2d(4+4). The computed dice count is rounded to the nearest whole number.

Modifiers

Modifiers attach to a roll to change its behaviour, and several can be combined on one roll. Most take an optional Compare Point (CP) to change their trigger.

Exploding

!CP rolls an extra die each time the maximum (or the CP) is rolled, and keeps going if the extra die also triggers.

• 3d6! - explode on a 6
• 3d6!>5 - explode on a 5 or 6
• 3d6!3 - explode only on a 3

Compounding

!!CP is like exploding, but all the extra rolls for a die are summed into that single die value.

• 5d6!! - compound on a 6
• 5d6!!5 - compound on a 5

Penetrating

!pCP is like exploding, but each extra die has 1 subtracted from it.

• 5d6!p - penetrate on a 6
• 5d6!p>5 - penetrate on a 5 or 6

Keep / Drop

khN / klN / dhN / dlN keeps or drops the N highest (h) or lowest (l) dice. kN defaults to keep-highest and dN to drop-lowest.

• 4d6kh3 - keep the highest 3 (drop the lowest)
• 2d20kl1 - keep the lowest 1 (disadvantage)
• 8d100dl3 - drop the lowest 3
• 8d100dh3 - drop the highest 3

Target Number / Successes

A bare Compare Point counts successes instead of summing: each die meeting the CP counts as one success. Remember >N is inclusive (N or higher).

• 3d6>3 - count d6s that roll 3 or higher
• 10d6<4 - count d6s that roll 4 or lower
• 2d6=6 - count exact 6s

Failures

fCP, only alongside a success check: each die meeting the failure CP subtracts one from the success count.

• 3d6>3f1 - success on 3 or higher, failure on each 1
• 10d6<4f>5 - success on 4 or lower, failure on 5 or higher

Rerolling

rCP rerolls a die (discarding the original) while it meets the CP, and can be repeated for several values.

• 2d8r<2 - reroll any 1 or 2
• 2d8r8 - reroll any 8
• 2d8r1r3r5r7 - reroll any odd result

Reroll Once

roCP is like reroll, but each die is rerolled at most once.

• 2d10ro<2 - reroll a 1 or 2, one time per die

Critical Success / Fumble

csCP / cfCP marks a roll as a critical success or fumble in the result display. This is a display marker only; it does not change the total.

• 1d20cs>18 - show an 18 or higher as a critical success
• 1d20cf<3 - show a 3 or lower as a fumble

Sorting

sa / sd sorts the dice results ascending (sa, or just s) or descending (sd).

• 8d6s - ascending
• 8d6sd - descending

Dice Matching

m / mt highlights (m) or counts (mt) matching dice. This is display-oriented and does not change the summed total.

• 20d6mt - count the matches
• 6d6mt3 - count matches only when there are 3 of a kind

Modifier Order

Exploding, compounding, penetrating, and rerolls are applied while the dice are still "rolling"; keep, drop, success, failure, and sorting are applied after all dice have settled.

Grouped Rolls

Wrap several sub-rolls in curly braces { }, separated by commas, then apply a group modifier across the whole group.

Group Keep / Drop

khN / klN / dhN / dlN applied to a group:

• {4d6+3d8}kh1 - keep the single highest die across both pools
• {4d6, 3d8}kh1 - keep the higher pool total
• {4d6+2d8, 3d20+3, 5d10+1}d1 - total each sub-roll, then drop the lowest total

Group Success / Failure

A Compare Point (and optional fCP) applied to a group:

• {3d20+5}>21 - add 5 to each d20, count 21 or more as a success
• {2d6!}>4 - explode 2d6, count 4 or higher as successes
• {4d6+2d8, 3d20+3, 5d10+1}>40f<10 - per sub-roll total: success at 40 or more, failure at 10 or less