A coin has two sides and one job: be fair. It is not quite fair. A person flipping a coin by thumb lands it on the side it started on about 51% of the time [1][2]. That one percent is where this post lives. Chance is the maths of what the dice do. Luck is the story we tell about…
A friend who has never played asked whether a D&D turn is like blackjack: learnable rules, so you never freeze when the table looks at you. It is. Both games compress to one law each. Blackjack: "the dealer has no choices, so play off what their up-card threatens." D&D: "actions are the currency, so spend yours to take away theirs."…
What Makes a Shape Worth Trusting. Five shapes are perfect. Rather more than five are fair. The difference is the whole story. What Makes a Die Fair The obvious answer is symmetry, and the obvious answer is very nearly right. It matters which symmetry, and the usual assumption asks for far more of it than a die needs. A die…
Dungeons & Dragons is a game where you say what your character does, the Dungeon Master (DM) says what happens, and a twenty-sided die settles every argument in between. That is the whole engine. Everything else is detail, and this guide gives you only the detail you need for your first night at the table. The rules here come from…
In March 2019, a group of voice actors who play D&D on camera every week asked their viewers for $750,000 to make an animated special. 88,887 people pledged $11,385,449 in 45 days [1]. That is Critical Role, and it is the ceiling. Your stream starts at the floor: three friends, one webcam, and a DM who talks too close to…
We are building a character sheet app. Native: Swift on iPhone and iPad, Kotlin on Android. Not a website in a shell, not a web view with an icon on it. The real thing, so it opens instantly, works with no signal in a basement, and feels like the rest of your phone. Before we build the wrong thing, we…
D&D runs on one idea: roll a d20, add a number, beat a number. Everything else is a footnote to that sentence, and this post is the footnotes, with the odds worked out so you know when to push your luck. Rules here are from the System Reference Document 5.2, the free version of the 2024 rules [1]. The 2014…
Players and Dungeon Masters roll the same dice for different reasons. A player rolls to find out whether the plan worked. The DM rolls to find out what the world does about it. Below: the rolls each side makes in the first hour of a game, the ten rolls that make a table lean in, and the four rolls of…
DnD Dice Roller has had its biggest update since it launched. Your dice lines can live on an account instead of in one browser, the save button is gone because the site saves as you go, and you can see, and choose, where your random numbers come from. Here is what changed and how to use it. Your dice lines…
Advantage and disadvantage are two of the most important dice rules in modern Dungeons & Dragons. They are also two of the easiest to explain badly. The rule, from the System Reference Document 5.2.1 (the free 2024 rules text, "Playing the Game", D20 Tests) [1]: Advantage: roll two d20s and use the higher. Disadvantage: roll two d20s and use the…
