Nobody quits DMing because they didn’t know the grappling rules. They quit because of the twelve seconds of silence after a player asks something the book doesn’t answer, and everyone looks at them, and they have no idea what to say.
That silence is the actual job. Looking up a rule is easy. Making a ruling is the thing you do forty times a night, mostly in under three seconds, mostly about situations Wizards never printed. This is a list of the fifty that come up most, what the rules actually say when they say anything, and a sentence you can say out loud at the table to keep the game moving.
Two ground rules before we start. Everything here uses the 2024 rules, and where the 2014 books did it differently in a way that matters, it’s flagged. And every one of these is a suggestion you’re allowed to overrule. You are the person who decides, and knowing the default makes deciding easier.
Start here: the four questions
The 2024 Dungeon Master’s Guide gives you a four-question flowchart for any situation you don’t recognize, and it resolves most of this article on its own.
Is a roll warranted? Only if there’s a real chance of both success and failure, and failure actually costs something. What kind of roll? Ability check if they’re doing something, saving throw if they’re resisting something, attack roll if they’re hitting something. Which ability? Whichever most affects the outcome, and be generous about letting a proficiency apply. What’s the DC? Ten for easy, fifteen for moderate, twenty for hard.
Memorize those four and you can bluff your way through anything on this list. The other forty-nine entries are just the common cases pre-solved.
Rolling dice
1. “Can I roll Persuasion?” No. Players don’t call for their own checks. They say what their character does and you decide whether that’s uncertain enough to need dice. Say: “Tell me what you say to him, and then I’ll tell you if you’re rolling.”
2. A player rolls before you ask for it. The die on the table is not a contract. You can ignore it. Say: “Hang on, what are you actually doing?” Then decide, then have them roll again if it turns out you need one. Do this from session one and it stops happening by session four.
3. They rolled a natural 20 on an ability check. A natural 20 does nothing special outside of attack rolls. It’s a 20 plus modifiers, same as any other number. The DMG explicitly suggests you can reward an exceptional roll with a better outcome (the twenty on an Investigation check turns up an extra clue), but the check still has to beat the DC. Say: “That’s a 24 total, and that beats it comfortably, so here’s a little extra.”
4. They rolled a natural 1 on an ability check. Same deal in reverse: it’s just a low number. And the DMG specifically warns you off inventing punishments for natural 1s, including on attack rolls, because a missed attack is already the punishment and your players will roll dozens of them. Nobody’s sword should shatter. Say: “That’s a miss.” Move on.
5. “I want to try again.” If failing costs nothing but time, don’t make them roll twice. Either tell them how long it takes, or make one roll and use the result to decide how long. Say: “You’ll get it eventually. It takes you about ten minutes, and the noise carries.”
6. Everybody wants to roll the same check. If five people roll Perception, someone hits a 19 and your secret door was never secret. Use one roll when one success is enough (the highest relevant character rolls, or use passive scores), and use a group check when the party is genuinely working together and the strong can cover for the weak. In a group check, everyone rolls and the group succeeds if at least half of them do.
7. When to use passive Perception instead. Passive Perception is 10 plus their Wisdom (Perception) modifiers, and it’s what a character notices without looking. Use it for anything the party would walk past. Rolling telegraphs that there’s something to find; passive scores don’t. Say nothing at all, which is the point.
8. Setting a DC on the fly. Ten, fifteen, or twenty. That’s the whole system. Five means don’t bother rolling and twenty-five and up are for genuinely superhuman tasks. For saving throws you invent yourself, stay between 10 and 20.
9. “Does my proficiency apply?” Usually yes, if they can explain it in one sentence. The DMG tells you outright to be generous here, and it suggests asking for a bare ability check and letting the player argue for a skill. A player who finds a reason their weird proficiency matters has just done your job for you. Say: “Sure. Make it an Intelligence check, and tell me which skill you think helps.”
Combat
10. “Can I do a cool thing that isn’t on my sheet?” Yes. Improvised actions are a rule, not a loophole. Set a DC, decide what success does, and price it against a normal attack so it isn’t strictly better. Say: “Give me an Athletics check against 15. If you make it, he’s prone and you don’t get your attack this turn.”
11. Damage for something you made up. The DMG’s improvising damage table: 1d10 for a falling bookcase or a poison needle, 2d10 for a lightning strike or stumbling into a firepit, 4d10 for rubble in a collapsing tunnel, 10d10 for whirling blades or wading through lava. At levels 1 to 4, 1d10 is a nuisance and 2d10 can kill somebody. Scale up from there by tier.
12. Hitting a player who has enormous AC. If the paladin is AC 21 and you’ve missed nine times, stop attacking the paladin. Monsters aren’t obligated to be stupid. Send things at the wizard, use effects that force saving throws instead of attack rolls, or have the enemy grapple and drag. Monsters that keep swinging at the one target they can’t hit make combat feel like a spreadsheet, and the tank feels great for about two rounds and bored for the rest.
13. Attacking a downed player. Legal, brutal, and almost always the wrong call. An attack against an unconscious creature has advantage, and any hit from within five feet is an automatic critical, which means two death save failures at once. So a single hit from an adjacent monster puts a downed character two-thirds of the way to dead before they roll anything. Use it when the monster is mindless or specifically cruel, and telegraph it the first time. Say: “The ghoul isn’t done with him.”
14. “I attack his weak point / I go for the eyes.” There are no called shots in 5e, and if you invent them you’ll be adjudicating them forever. Reskin instead of remechanizing. Say: “Roll a normal attack, and if you hit, I’ll describe it going in the eye.”
15. Flanking. Not a rule in either the 2014 or 2024 core game. It’s an optional variant, and the version everybody remembers (advantage for standing on opposite sides) makes advantage so easy to get that it flattens rogues and reduces most fights to a shuffle. If you want to reward positioning, use the Help action, which already does this.
16. Cover, quickly. Half cover is +2 to AC and Dexterity saves, three-quarters is +5, total cover means you can’t be targeted at all. Only the best one applies, they never add together, and it only counts if the attack comes from the other side of it.
17. Advantage stacking. It doesn’t. Three sources of advantage is still one advantage, and a single source of disadvantage cancels the whole pile. Say: “You’ve got advantage and disadvantage, so they cancel. Roll one die.”
18. Prone is not simple. A prone creature has disadvantage on its own attacks. Attacks against it have advantage from within five feet and disadvantage from further away. So knocking the archer prone helps your melee and hurts your ranged party, and diving prone behind a wall against a sniper is a legitimately smart move.
19. Grappling in 2024. A grapple is made with an Unarmed Strike, needs a free hand, and can only hold one creature per hand. Grappled means speed 0 and disadvantage on attacks against anyone but the grappler. Escaping takes the grappled creature’s action and a Strength (Athletics) or Dexterity (Acrobatics) check against the escape DC. The grapple also just ends if the grappler gets incapacitated.
20. Opportunity attacks. They trigger when a creature you can see leaves your reach using its movement, action, bonus action, or reaction. Not when it moves around inside your reach, not when it’s shoved or teleported, and not if you can’t see it.
21. “I ready an action.” Fine, but make them name the trigger and the response before you move on, because the trigger is the whole rule. Say: “What exactly are you waiting for, and what do you do when it happens?”
22. Initiative ties. The 2024 rules settle this outright: the DM decides the order among tied monsters, the players decide among tied characters, and the DM decides when a monster ties a player. Let the players argue about their half for exactly five seconds; it’s a free moment of tactics.
23. Surprise in 2024. Surprised creatures no longer lose a turn. They have disadvantage on their initiative roll, and that’s it. This is a big change from 2014 and it’s the most common thing veteran DMs run wrong at a 2024 table.
24. Two things happen at the same instant. Whoever’s turn it is decides the order. That’s an actual printed rule and it settles more arguments than you’d think.
25. Improvised weapons. 1d4, no proficiency bonus, and the DM can rule that a thing which resembles a real weapon just uses that weapon’s stats. A table leg is a club. Let it be a club.
26. Hiding in the middle of a fight. Hiding requires a DC 15 Dexterity (Stealth) check while heavily obscured or behind three-quarters cover, and out of every enemy’s line of sight. Success gives them the Invisible condition, and their check total becomes the DC for anyone searching. The moment they attack or make noise above a whisper, it’s over. This is stricter than most tables play it, and it’s a mercy, because it gives you a number to say no with.
27. A player wants to do something in the dark. Darkness is heavily obscured, which means you’re effectively blinded looking into it: attacks against anything in there have disadvantage, and anything in there attacking out has advantage. Dim light is only lightly obscured, which is just disadvantage on Perception checks to see. Darkvision turns darkness into dim light, so a character with darkvision in a pitch black room still has disadvantage on Perception, and sees only shades of gray.
Dropping to 0 and dying
28. Death saves, exactly. Roll a d20 at the start of each turn you begin at 0 HP. Ten or higher succeeds. Three successes and you’re stable, three failures and you’re dead, and they don’t have to be consecutive. Natural 20 means you get up with 1 hit point. Natural 1 counts as two failures. Everything resets the moment you regain any hit points.
29. Somebody hits the downed character. Any damage at 0 HP is one automatic death save failure. If it was a critical, two. If the damage equals or exceeds their hit point maximum, they die instantly, no saves.
30. The huge hit that drops them. Massive damage: if the overflow past 0 is equal to or greater than their hit point maximum, they’re dead on the spot. A 12 HP character sitting at 6 who takes 18 has 12 left over, and 12 is their max, so they die. Check this before you narrate.
31. Healing someone at 0. Any healing at all wakes them up at that many hit points and wipes the death save track. Temporary hit points do not, because temp HP isn’t healing and isn’t hit points. Say: “Cure Wounds for four? He’s up with 4.”
32. Stabilizing without a healer. Take the Help action and make a DC 10 Wisdom (Medicine) check. A stable creature stops rolling death saves but stays unconscious, and comes back with 1 hit point after 1d4 hours. Any damage un-stabilizes them.
33. “I want to knock him out, not kill him.” Only on a melee attack, and it’s the attacker’s choice: instead of dropping the target to 0, you drop them to 1 and give them the Unconscious condition. They start a short rest and wake at the end of it, or earlier if healed or given first aid on a DC 10 Wisdom (Medicine) check.
34. A player is about to die and you don’t want them to. Decide before the dice hit the table which kind of DM you are, and be that consistently. Rolling in the open means you can’t take it back, which is the point of rolling in the open. If you’d rather have the out, roll behind the screen and never mention it. What you must not do is roll in the open and then fudge, because your table can see the die.
35. Monsters at 0 HP. A monster dies the instant it hits 0. That’s the default, and the rules explicitly let you ignore it for any individual monster you’d rather have survive. Say: “He goes down, but he’s still breathing.”
Spells and magic items
36. Concentration, the short version. One concentration effect at a time, and starting a second one ends the first. Taking damage forces a Constitution save at DC 10 or half the damage taken, whichever is higher, capped at 30. Concentration also ends if the caster is incapacitated or dies.
37. “Can I concentrate on two things?” No. This one is worth a firm no, because it’s the single most load-bearing balance rule in the game.
38. A player wants to flavor a spell differently. Say yes. Same damage, same range, same save, different description: their Fireball is a swarm of screaming ravens, their Eldritch Blast is a thrown playing card. It costs you nothing and it’s most of what makes a table feel like your table. The only line is when the reflavor tries to change the damage type or dodge a resistance, and then it’s a no with a reason.
39. Ritual casting. A prepared spell with the Ritual tag can be cast as a ritual: ten minutes longer, no spell slot, and it can’t be cast at a higher level that way.
40. Do you enforce material components? Pick one policy tonight. Either a component pouch or focus covers everything without a listed cost and you never think about it again, or you track the costly ones only (the 25 gp diamond dust, the 300 gp diamond for Revivify) because those are deliberate money sinks. Tracking bat guano is a joke everyone stops laughing at in session three.
41. Attunement, the parts people forget. Three items maximum, attuning takes a short rest focused on that one item, and attunement ends if the item is more than 100 feet away for 24 hours or if someone else attunes to it. And an item that requires attunement still works as a mundane version of itself if you haven’t attuned.
42. “What does this magic item do?” Identify is the fast way; otherwise a character can spend a short rest in contact with the item and learn its properties, but never its curse. A taste is enough to identify a potion. That’s all printed, and it means you can stop worrying about whether to just tell them.
Talking to people
43. “I roll to persuade the king.” In 2024 this is the Influence action, and the important part is that the DM decides before any dice whether a check even happens. If the request lines up with what the creature wants, it just works. If it’s repugnant to them, it just fails. You only roll for the genuinely uncertain middle. Say: “He’s not going to hand over the crown for any roll. But he might give you the guards. Tell me how you pitch that.”
44. Persuasion versus Deception versus Intimidation. The player picks by describing the approach, not by comparing their modifiers. Then you name the skill. If they describe a threat, it’s Intimidation even if their Persuasion is higher.
45. Insight versus a lying NPC. You are allowed to just answer. “He’s nervous but he believes what he’s saying” is a better result than a number, and it doesn’t hand the party a lie detector. If you do roll, roll it against the NPC’s Deception, and remember that a bad Insight roll should give a vague answer, not a false one, because false information from a failed roll teaches players to distrust their own successes.
46. One player is doing all the talking. Not a rules problem, but you’ll fix it with a ruling: have NPCs address other characters by name and ask them direct questions. The quiet player doesn’t need to be encouraged, they need to be spoken to.
Resting, moving, and breaking things
47. Long rests, precisely. Eight hours, at least six of them asleep, no more than two hours of light activity, and you must wait 16 hours after finishing one before starting another (so no two long rests in a day). It’s interrupted by rolling initiative, among other things. You need at least 1 hit point to start one. Short rests are one hour and are interrupted by rolling initiative, taking any damage, or casting anything above a cantrip, and an interrupted short rest gives nothing.
48. Exhaustion in 2024 is much harsher. Every level subtracts twice the level from every d20 test and cuts 5 feet of speed per level. Six levels kills you. One level is a real penalty now, so it’s an excellent consequence for the failed forced march, and a terrible one to hand out casually.
49. Jumping and lifting, so you can stop guessing. Long jump is your Strength score in feet with a 10-foot run-up, half that standing. High jump is 3 plus your Strength modifier, half standing. Carrying capacity is Strength times 15 for a Small or Medium creature. Every foot of jumping costs a foot of movement.
50. “I break the door.” Objects have suggested ACs by material (11 for rope or paper, 13 for glass, 15 for wood, 17 for stone, 19 for iron) and small hit point totals: a chest is around 10, a barrel around 18. Objects are immune to poison and psychic damage. But before you reach for any of that, ask whether the door failing matters. If the only consequence of breaking it is noise, skip the roll and charge them the noise.
The one that isn’t on the list
You will get one of these wrong tonight. The fix is one sentence: “Here’s how we’re playing it tonight, and I’ll look it up before next session.”
That sentence has never once caused a problem at a table. Twenty-minute rulebook searches have caused thousands. Make the call, write it on a sticky note, check it later, tell them if you were wrong. Players forgive wrong rulings instantly and they never forgive a session that stopped moving.
And if you’d rather spend your prep time on the story instead of the flowchart, that’s more or less why we wrote the Big Book of Little Adventures: 200+ short, ready-to-run encounters where the hard decisions are already made, so the only rulings left are the fun ones.
Sources
- Player’s Handbook (2024), Wizards of the Coast. Rolling 20 or 1 on attack rolls, p. 12. Heroic Inspiration, p. 13. Initiative and surprise, p. 23. Difficult terrain, p. 24. Cover, p. 25. Opportunity attacks, p. 26. Critical hits, p. 27. Dropping to 0 hit points, instant death, massive damage, falling unconscious, and knocking out a creature, p. 28. Death saving throws, rolling a 1 or 20 on a death save, damage at 0 hit points, stabilizing a character, and temporary hit points, p. 29. Passive Perception, p. 40. Attunement, p. 232. Rules glossary definitions (advantage, concentration, darkness, dim light, exhaustion, grappled, grappling, heavily obscured, high jump, improvised weapons, invisible, knocking out a creature, lightly obscured, long jump, long rest, prone, restrained, ritual, round down, short rest, simultaneous effects, stable, surprised, unconscious, breaking objects, carrying capacity, damage threshold), pp. 360 to 377. Action definitions (Attack, Dash, Disengage, Dodge, Help, Hide, Influence, Magic, Opportunity Attack, Ready, Search, Study, Utilize), pp. 361 to 377.
- Dungeon Master’s Guide (2024), Wizards of the Coast. Resolving outcomes and the four adjudication questions, trying again, group checks, and passive checks, pp. 27 to 28. Setting a difficulty class and the Typical DCs table, p. 29. Natural 20s and 1s on ability checks and saving throws, and the improvising damage table, p. 30. Improvising answers (“Yes, and” / “No, but”), p. 31.
- Player’s Handbook (2014) and Dungeon Master’s Guide (2014), Wizards of the Coast, for the 2014 comparisons noted in entries 15, 19, and 23. Flanking appears in the 2014 Dungeon Master’s Guide as an optional rule, not a core one.
- All rules text and page numbers were checked against the published books before publication.
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