Dice add randomness to the game. They help determine whether characters and monsters are successful at the things they attempt.
The dice used in D&D are referred to by the letter d followed by the die’s number of sides: d4, d6, d8, d10, d12, and d20. For instance, a d6 is a six-sided die (the cube that many games use). The illustration on this page shows what each die looks like.
When you need to roll dice, the rules tell you how many dice to roll of a certain type, along with any numbers to add or subtract. For example, “3d8 + 5” means you roll three eight-sided dice, add them together, and add 5 to the total.
Round Down
Whenever you divide or multiply a number in the game, round down if you end up with a fraction, even if the fraction is one-half or greater. Some rules make an exception and tell you to round up.
The rules sometimes refer to a d100. While such dice exist, the common way to roll 1d100 uses a pair of ten-sided dice numbered from 0 to 9, known as percentile dice. One die—that you designate before rolling—gives the tens digit, and the other gives the ones digit. If you roll a 7 for the tens digit and a 1 for the ones digit, for example, the number rolled is 71. Two 0s represent 100.
Some ten-sided dice are numbered in tens (00, 10, 20, and so on), making it easier to distinguish the tens digit from the ones digit. In this case, a roll of 70 and 1 is 71, and 00 and 0 is 100.
The same d notation appears in the expression “1d3,” even though it’s rare to find dice with only three sides. To simulate rolling 1d3, roll 1d6 and divide the number rolled by 2 (round up).
Here are the most common uses of dice in D&D.
The 20-sided die (d20) is the most important die you’ll use in the game. It’s central to the core mechanic—called D20 Tests—the game uses to determine whether creatures succeed or fail at the things they attempt during the game (see “D20 Tests” later in this chapter). You roll a d20 whenever your character tries to do something that the DM decides has a chance of both success and failure. The higher your roll, the more likely it is that you succeed.
The most common use for dice other than the d20 is to determine damage. When you make a successful attack roll (one kind of D20 Test), you roll damage to see how effective the attack is. When you cast a spell, you might also roll damage. Different weapons and spells use different dice for damage. For example, a Dagger uses 1d4, a Greataxe uses 1d12, and a Fireball spell uses 8d6.
Occasionally, you’ll see a table that uses a die roll to generate a random result. On these tables, you’ll see a die expression, such as d10 or d100, in the header of the leftmost column. Roll that die, and find the number you rolled (or a range containing that number) in that column. Read across that row for the result. For example, the Trinkets table in chapter 2 uses a d100.
Sometimes you might see a rule describing a percentage chance of something happening. For example, a rule might say there is a 5 percent chance of something happening. You can determine whether that thing happens by rolling percentile dice; if the roll is equal to or less than the percentage chance (a 01 to 05, in this example), it happens.
Interpreting Die Rolls in the Story
Part of the fun of D&D is interpreting what die rolls mean in the story. The randomness that dice bring often introduces the unexpected: an expert fails, a novice succeeds, or any number of other twists. When a D20 Test or another roll produces a surprise, the Dungeon Master often gives a fun description of what happened. If you’re a player, look for opportunities to interpret your character’s die rolls and describe why things unfolded unexpectedly or even humorously.
