A Deep Dive Into Rolling Dice: The Mechanics of Tabletop RPGs

Jason Dookeran
5 min readAug 11, 2023


Knock on the Door. You know you want to.

The role of random chance in determining outcomes is a crucial part of tabletop roleplaying and adds to the excitement of a game. Recently (well, over the last few years at least), a friend has been involved in writing a tabletop RPG. He’s spent a lot of hours looking at the details of what makes a good (and balanced) RPG. Over this time, he’s also explored how dice can affect game successes and failures. Here, I’ll look at some of the conclusions my friend and I have come across designing and building video games that use dice as an integral part of interacting with the world.

Introducing Dice Rolling

Yes, they have more than six sides

Dice are an integral part of TTRPGs, used to determine the outcomes of actions taken by players in the game. Dice rolls are typically used to determine the success or failure of actions and the degree of success or failure. For example, players might roll dice to determine whether their character successfully picks a lock or hits an enemy in combat.

Types of Dice in TTRPGs

A full set of polyhedral dice

The type and number of dice used in TTRPGs vary depending on the game system used. D&D, for example, uses a variety of dice, including a 4-sided die (d4), a 6-sided die (d6), an 8-sided die (d8), a 10-sided die (d10), a 12-sided die (d12), and a 20-sided die (d20). Other game systems, such as Apocalypse World, may use only one or two types of dice.

When a player needs to make a dice roll, they will typically roll one or more dice and add or subtract any relevant modifiers. Modifiers can include attributes such as strength or dexterity and bonuses or penalties from items, spells, or other game mechanics. The total number obtained from the dice roll and modifiers is compared to a target number set by the GM, which determines whether the action was successful or not.

In D&D, for example, a player might roll a d20 to determine whether their character successfully hits an enemy in combat. If the player’s roll plus their attack bonus is equal to or greater than the enemy’s armor class (AC), the attack hits. In other game systems, the target number may be a fixed number that does not change.

Dice pool mechanics can add an additional level of complexity to the game, as players must calculate the number of successes achieved based on the number of dice rolled and the target number. However, they can also lead to exciting moments where players achieve multiple successes on a single roll, resulting in impressive feats or actions.

Sliding Scales of Success

Not all successes are epic successes

Dice rolls can also determine the degree of success or failure. For example, in D&D, if a player rolls a 20 on a d20, this is called a critical hit and typically results in extra damage or other benefits. Conversely, if a player rolls a one on a d20, this is called a critical miss or fumble and may result in penalties or negative consequences.

Some game systems use dice rolls to determine random events or outcomes, such as deciding the weather or the likelihood of finding treasure. In these cases, the GM will set a target number based on the possibility of the event occurring, and the players will roll dice to determine whether the event happens or not.

The Fickle Fate of a Die Roll

Yep, this could happen to you

Dice rolls can also be used to add a level of unpredictability or excitement to the game. Because dice rolls are random, players never know for sure whether their actions will be successful or not. This can lead to tense, exciting moments where the fate of the characters is uncertain.

In addition to standard dice rolls, some game systems use dice pool mechanics. In these systems, players roll several dice and count the number of successes achieved. For example, in the World of Darkness game system, players might roll a pool of 10-sided dice and count the number of rolls equal to or greater than a target number set by the GM.

Dice rolls are an essential part of tabletop roleplaying games, used to determine the outcomes of actions taken by players. Different game systems use different types and numbers of dice, as well as different modifiers and target numbers. In my decade as a DM, I have seen all sorts of rolls in tabletop RPGs. I’ve seen players roll multiple critical hits and seen others miss on what should be guaranteed successes. Dice are your lifeline in a tabletop game. Take care of them, and they’ll take care of you.

Hello, and welcome to my blog. I’m Jason, a DM for over a decade and a dabbler in coding, AI, Tech, and travel. My blog’s filled with articles like these, along with some advice from my years of experience. If you’re interested in this type of content or want to suggest something to me, follow me on Medium, comment on my post, or email me at jdookeran@gmail.com. I’ll be looking forward to hearing from you!



Jason Dookeran

Freelance author, ghostwriter, and crypto/blockchain enthusiast. I write about personal finance, emerging technology and freelancing