General Rules

General Rules

The basic rules shown are from the System Reference Document and part of the 5th Edition Open Game License.

Game Dice
The D20
Advantage and Disadvantage
Round Down
Armor Class
Alignment
Inspiration

Game Dice

The game uses polyhedral dice with different numbers of sides. You can find dice like these in game stores and in many bookstores.

In these rules, the different dice are referred to by the letter d followed by the number of sides: d4, d6, d8, d10, d12, and d20. For instance, a d6 is a six-sided die (the typical cube that many games use). Percentile dice, or d100, work a little differently. You generate a number between 1 and 100 by rolling two different ten-sided dice numbered from 0 to 9. One die (designated before you roll) gives the tens digit, and the other gives the ones digit. If you roll a 7 and a 1, 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.

When you need to roll dice, the rules tell you how many dice to roll of a certain type, as well as what modifiers to add. For example, “3d8 + 5” means you roll three eight-sided dice, add them together, and add 5 to the total.

The same d notation appears in the expressions “1d3” and “1d2.” To simulate the roll of 1d3, roll a d6 and divide the number rolled by 2 (round up). To simulate the roll of 1d2, roll any die and assign a 1 or 2 to the roll depending on whether it was odd or even. (Alternatively, if the number rolled is more than half the number of sides on the die, it’s a 2.)

The D20

In cases where the outcome of an action is uncertain, the Dungeons & Dragons game relies on rolls of a 20-sided die, a d20, to determine success or failure.

Every character and monster in the game has capabilities defined by six ability scores. The abilities are Strength, Dexterity, Constitution, Intelligence, Wisdom, and Charisma, and they typically range from 3 to 18 for most adventurers. (Monsters might have scores as low as 1 or as high as 30.) These ability scores, and the ability modifiers derived from them, are the basis for almost every d20 roll that a player makes on a character’s or monster’s behalf.

Ability checks, attack rolls, and saving throws are the three main kinds of d20 rolls, forming the core of the rules of the game. All three follow these simple steps.

1. Roll the die and add a modifier. Roll a d20 and add the relevant modifier. This is typically the modifier derived from one of the six ability scores, and it sometimes includes a proficiency bonus to reflect a character’s particular skill. (See chapter 1 for details on each ability and how to determine an ability’s modifier.)

2. Apply circumstantial bonuses and penalties. A class feature, a spell, a particular circumstance, or some other effect might give a bonus or penalty to the check.

3. Compare the total to a target number. If the total equals or exceeds the target number, the ability check, attack roll, or saving throw is a success. Otherwise, it’s a failure. The DM is usually the one who determines target numbers and tells players whether their ability checks, attack rolls, and saving throws succeed or fail. The target number for an ability check or a saving throw is called a Difficulty Class (DC). The target number for an attack roll is called an Armor Class (AC).

This simple rule governs the resolution of most tasks in D&D play. 

Advantage and Disadvantage

Sometimes an ability check, attack roll, or saving throw is modified by special situations called advantage and disadvantage. Advantage reflects the positive circumstances surrounding a d20 roll, while disadvantage reflects the opposite. When you have either advantage or disadvantage, you roll a second d20 when you make the roll. Use the higher of the two rolls if you have advantage, and use the lower roll if you have disadvantage. For example, if you have disadvantage and roll a 17 and a 5, you use the 5. If you instead have advantage and roll those numbers, you use the 17.

Round Down

There’s one more general rule you need to know at the outset. Whenever you divide a number in the game, round down if you end up with a fraction, even if the fraction is one-half or greater.

Armor Class

Your Armor Class (AC) represents how well your character avoids being wounded in battle. Things that contribute to your AC include the armor you wear, the shield you carry, and your Dexterity modifier. Not all characters wear armor or carry shields, however.

Without armor or a shield, your character’s AC equals 10 + his or her Dexterity modifier. If your character wears armor, carries a shield, or both, calculate your AC using the rules in the armor section (link forthcoming).

Your character needs to be proficient with armor and shields to wear and use them effectively, and your armor and shield proficiencies are determined by your class. There are drawbacks to wearing armor or carrying a shield if you lack the required proficiency.

Some spells and class features give you a different way to calculate your AC. If you have multiple features that give you different ways to calculate your AC, you choose which one to use.

Alignment

A typical creature in the worlds of Dungeons & Dragons has an alignment, which broadly describes its moral and personal attitudes. Alignment is a combination of two factors: one identifies morality (good, evil, or neutral), and the other describes attitudes toward society and order (lawful, chaotic, or neutral). Thus, nine distinct alignments define the possible combinations.

These brief summaries of the nine alignments describe the typical behavior of a creature with that alignment. Individuals might vary significantly from that typical behavior, and few people are perfectly and consistently faithful to the precepts of their alignment.

  • Lawful good (LG) creatures can be counted on to do the right thing as expected by society. Gold dragons, paladins, and most dwarves are lawful good.
  • Neutral good (NG) folk do the best they can to help others according to their needs. Many celestials, some cloud giants, and most gnomes are neutral good.
  • Chaotic good (CG) creatures act as their conscience directs, with little regard for what others expect. Copper dragons, many elves, and unicorns are chaotic good.
  • Lawful neutral (LN) individuals act in accordance with law, tradition, or personal codes. Many monks and some wizards are lawful neutral.
  • Neutral (N) is the alignment of those who prefer to steer clear of moral questions and don’t take sides, doing what seems best at the time. Lizardfolk, most druids, and many humans are neutral.
  • Chaotic neutral (CN) creatures follow their whims, holding their personal freedom above all else. Many barbarians and rogues, and some bards, are chaotic neutral.
  • Lawful evil (LE) creatures methodically take what they want, within the limits of a code of tradition, loyalty, or order. Devils, blue dragons, and hobgoblins are lawful evil.
  • Neutral evil (NE) is the alignment of those who do whatever they can get away with, without compassion or qualms. Many drow, some cloud giants, and yugoloths are neutral evil.
  • Chaotic evil (CE) creatures act with arbitrary violence, spurred by their greed, hatred, or bloodlust. Demons, red dragons, and orcs are chaotic evil.

Most creatures that lack the capacity for rational thought do not have alignments—they are unaligned.

Inspiration

Inspiration is a rule the Dungeon Master can use to reward you for playing your character in a way that’s true to his or her personality traits, ideal, bond, and flaw.

Gaining Inspiration

Your DM can choose to give you inspiration for a variety of reasons. Typically, DMs award it when you play out your personality traits, give in to the drawbacks presented by a flaw or bond, and otherwise portray your character in a compelling way. Your DM will tell you how you can earn inspiration in the game.

You either have inspiration or you don’t—you can’t stockpile multiple “inspirations” for later use.

Using Inspiration

If you have inspiration, you can expend it when you make an attack roll, saving throw, or ability check. Spending your inspiration gives you advantage on that roll.

Additionally, if you have inspiration, you can reward another player for good roleplaying, clever thinking, or simply doing something exciting in the game. When another player character does something that really contributes to the story in a fun and interesting way, you can give up your inspiration to give that character inspiration.

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