Dice Expressions

Every roll in Encounter+ goes through the same parser, so the syntax on this page works wherever a formula is accepted. For how rolling fits into play — the roller, roll tables, rolls in text — see Dice & Roll Tables.

Where expressions are accepted

Place	Notes
The dice roller’s custom formula field	The full syntax
Dice in rendered text	Found automatically, or written as [2d6+3](roll) — see Writing Content
A roll table’s first column name	d100, d20 — decides how rows are matched
Hit point formulas on a creature	4d8+12 rolls average or random hit points
Initiative formulas	From the game system’s initiative configuration
The web client chat	/roll 2d6+3 or /r 2d6+3 — see Remote Play
Roll links in content	/roll/<formula>/<name>/<type>

Expressions are case-insensitive and whitespace is ignored, so 2D6 + 3 and 2d6+3 are the same.

Dice

[count]d<faces>[modifier]

count is optional and defaults to 1, so d20 and 1d20 are identical. faces is required.

d20        one twenty-sided die
4d6        four six-sided dice, summed
2d10       two ten-sided dice
100d6      one hundred six-sided dice

Any number of faces works, not just the physical dice — d7, d3 and d1000 are all valid.

The bare modifier shorthand

An expression that is only a signed number is read as a d20 roll with that modifier — the common case of tapping a +7 in a stat block.

+7    →  d20 + 7
-2    →  d20 - 2

Arithmetic

Dice and numbers can be combined with the usual operators:

Operator	Meaning
+	Add
-	Subtract
*, x, ×	Multiply
/, ÷	Divide
( )	Group

Multiplication and division bind tighter than addition and subtraction, and brackets override that.

2d6 + 3
1d8 + 1d6 + 4
(1d6 + 3) * 2
d6 x (100 + d6)
4d6 / 2

Whole numbers only

Everything is integer arithmetic. Division truncates — 7/2 is 3 — and a division by zero is not evaluated at all.

Modifiers

A modifier is written directly after the die, with no space. Most take an optional comparison and a number; where one is omitted the default in the table applies.

Modifier	Name	Default	What it does
kh[n]	Keep highest	kh1	Keeps the n highest dice, discards the rest
kl[n]	Keep lowest	kl1	Keeps the n lowest dice, discards the rest
dh[n]	Drop highest	dh1	Discards the n highest dice
dl[n]	Drop lowest	dl1	Discards the n lowest dice
r[cmp]<n>	Reroll	r1	Rerolls any matching die, repeatedly, until it no longer matches
ro[cmp]<n>	Reroll once	ro1	Rerolls any matching die exactly once, keeping the new value whatever it is
![cmp]<n>	Explode	max face	Adds an extra die for every matching die, and keeps going while the new die also matches
!o[cmp]<n>	Explode once	max face	Adds one extra die for every matching die, and stops there
cs[cmp]<n>	Count successes	cs1	The result becomes the number of matching dice, not their sum
cf[cmp]<n>	Count failures	cf1	The result becomes the number of matching dice, counted as failures
df[cmp]<n>	Deduct failures	df1	Sums the dice, then subtracts 1 from the total for each matching die
sf[cmp]<n>	Subtract failures	sf1	Sums the dice, with each matching die subtracted instead of added

Discarded and rerolled dice are not thrown away in the display — they stay in the roll detail with a ☓ beside them, so you can see what the dice actually did.

Comparison operators

r, ro, !, !o, cs, cf, df and sf all take an optional comparison in front of their number:

Written	Matches
= or nothing	Equal to
>	Greater than
>=	Greater than or equal
<	Less than
<=	Less than or equal

So r1 and r=1 are the same, and r<3 rerolls anything under 3.

Examples

2d20kh1        advantage — roll two d20, keep the higher
2d20kl1        disadvantage
4d6dl1         ability score — roll four d6, drop the lowest
4d6r1          great weapon fighting — reroll 1s until they are not 1s
4d6ro<3        reroll 1s and 2s, once each
2d6!           exploding sixes, chaining
2d6!o          one extra die per six, no chain
1d10!>=8       explode on 8, 9 or 10
6d10cs>=7      count how many dice rolled 7 or better — a result of 3 is three successes
10d6sf<3       sum the dice, subtracting any that rolled under 3

One modifier per die

A die group takes a single modifier. 4d6dl1kh2 is not stacked — parsing stops at the second modifier and the rest of the expression is dropped. Combine dice in separate groups instead, or pick the one modifier that expresses what you want.

Advantage, disadvantage and criticals

The roller can upgrade an expression rather than making you rewrite it:

Upgrade	Effect
Advantage	Every d20 in the expression becomes 2d20kh1; other dice are untouched
Disadvantage	Every d20 becomes 2d20kl1
Critical	Every die’s count is doubled — 2d6+3 becomes 4d6+3

Advantage and disadvantage replace any modifier already on the d20, so a formula written with kh by hand and then rolled with advantage does not compound.

Roll names and types

A roll can carry a label and a type, which is what lets the roll log tell one roll from another and what selects the dice theme it is rolled with.

The types are attack, damage, heal, check and save.

In Markdown, the label is the link title and the full form is a path:

[2d6+3](roll "fire damage")
[+7](/roll/d20+7/Longsword/attack)

In the web client chat, the label goes in brackets, optionally with the type after a colon:

/roll 2d6+3 [Fire damage]
/roll d20+7 [Longsword: attack]

Under D&D 5E the app also guesses the type when none is given — a leading + reads as an attack, a d20 as a check, and a formula near the word damage as damage.

Limits and edge cases

• Dice count and faces are each capped at 1,000,000.
• Rerolling and exploding stop after about 100 extra dice per die, so d6! on a run of sixes terminates rather than hanging.
• Roll detail — a group of more than 10 dice reports only its total; the individual rolls are not listed or sent to players.
• Thousands separators in a number are ignored: 1,000d6 is a thousand d6.
• Automatic detection in text is narrower than the parser. Prose is scanned for the plain 2d6+3 shape only, so an expression with !, r, cs or brackets in it has to be written as an explicit (roll) link to become tappable.
• An unparseable expression produces no roll at all rather than a partial one — in chat it comes back as Invalid expression.

Where to go next

• Dice & Roll Tables — the roller, rolls in content, and roll tables.
• Writing Content — dice inside Markdown, and links to your own content.
• Dice Roller Settings — rollers, random generator, sound and themes.
• URL Scheme — opening the app with a link.