How to Set DCs in D&D 5e: A Complete Game Master Guide

You've got a player who wants to leap across a flaming chasm while carrying an unconscious halfling. Another wants to convince the guard captain they're a visiting diplomat. A third is trying to recall whether mind flayers are vulnerable to sunlight.

What number do you set?

If you've been running D&D for a while, you probably eyeball it and move on. If you're newer, you might freeze up, pick something random, or default to DC 15 for everything. Neither approach is great.

Setting the right DC is one of the most important GM skills in D&D 5e, and the official rules give you about half a page on the topic. If you're just getting started behind the screen, our first-time DM guide covers the broader picture. Here's the rest on DCs specifically.

The D&D 5e DC Chart

This is the standard Difficulty Class table from the Dungeon Master's Guide (p. 238). Commit it to memory — it's the foundation for every check you'll ever call for.

| DC | Difficulty | What It Means | |---|---|---| | 5 | Very Easy | Almost anyone can do this. Barely worth rolling. | | 10 | Easy | A trained character handles this routinely. | | 15 | Medium | Requires focus or skill. The default "meaningful check." | | 20 | Hard | Even skilled characters fail often. | | 25 | Very Hard | Exceptional talent or luck required. | | 30 | Nearly Impossible | Legendary. Most characters cannot succeed. |

Most of your session will live in the DC 10–20 range. DC 5 is so easy it rarely needs a roll. DC 25+ should appear sparingly — these are moments of genuine drama, not Tuesday afternoon.

What DCs Actually Mean (The Math)

Understanding the probability behind DCs makes you a better GM. Here's what the numbers look like for different characters:

| DC | Untrained (+0) | Decent (+3) | Good (+5) | Expert (+8) | Master (+11) | |---|---|---|---|---|---| | 10 | 55% | 70% | 80% | 95% | 100% | | 15 | 30% | 45% | 55% | 70% | 85% | | 20 | 5% | 20% | 30% | 45% | 60% | | 25 | — | — | 5% | 20% | 35% |

A character with a +5 modifier fails a DC 15 check 45% of the time. That's not trivial — it's a genuine challenge. A DC 20 check at +5 fails 70% of the time. Keep that in mind before you start throwing DC 20s around casually.

When to Call for a Check (And When Not To)

Before you even think about setting a DC, ask yourself two questions:

1. Can this task fail in an interesting way?

If the answer is no, don't roll. The fighter with 20 Strength can kick down a rotting wooden door. The wizard with Arcana expertise recognizes a common cantrip. No roll needed. Calling for checks on trivial tasks wastes time and makes your players feel like their character investments don't matter.

2. Is success even possible?

A character with a −1 modifier cannot hit DC 25. Period. If the task is beyond the character's capability, either don't allow the attempt or describe why it fails without a roll. No amount of luck should let the 8-Strength wizard bench press a boulder.

The "nothing happens" trap is the most common mistake new GMs make - and it applies to combat encounters just as much as skill checks. The rogue fails to pick the lock. Now what? The party stands around. Nobody's having fun. Instead, make failure interesting: the lockpick snaps inside (now it's harder), the noise attracts a guard, or the rogue realizes this lock requires a specific key — redirecting the party toward a different approach.

Setting DCs for Every Situation

Routine Tasks: DC 10

The character is trained and the conditions are normal. Think of DC 10 as "a professional on a regular day."

• Athletics DC 10: Climbing a rough stone wall with handholds
• Arcana DC 10: Identifying a common spell being cast
• Persuasion DC 10: Asking a friendly shopkeeper for a small discount
• Stealth DC 10: Moving quietly through an empty corridor
• Medicine DC 10: Stabilizing a dying creature (this is actually RAW)

Real Challenges: DC 15

The default for anything that should feel like a real test. DC 15 means "you need to be good at this OR get lucky."

• Athletics DC 15: Swimming against a moderate current
• Investigation DC 15: Finding a hidden compartment in a desk
• Deception DC 15: Lying convincingly to a suspicious guard
• Perception DC 15: Noticing a creature hiding in the shadows
• Survival DC 15: Tracking a creature across hard ground after rain

Hard Tests: DC 20

Reserve these for moments that should feel tense. DC 20 says "even experts fail more often than they succeed."

• Acrobatics DC 20: Walking a tightrope in high winds
• Intimidation DC 20: Making a battle-hardened veteran flinch
• History DC 20: Recalling the name of an obscure kingdom from 500 years ago
• Nature DC 20: Identifying a rare magical plant by sight alone
• Sleight of Hand DC 20: Picking a pocket in the middle of a conversation with the mark

Extreme Tests: DC 25–30

These should be rare. DC 25 is "once in a campaign" territory. DC 30 is legendary.

• Athletics DC 25: Holding a collapsing stone archway while the party runs through
• Persuasion DC 25: Convincing a hostile king to pardon someone he publicly sentenced
• Stealth DC 25: Sneaking past a dragon in its own lair
• Arcana DC 30: Recalling the true name of a sealed archdevil from a fragment of text

Setting DCs for Homebrew Situations

This is where most GMs actually struggle. The book doesn't have a DC for "convincing a sentient door to let you through" or "using Performance to distract a hive of angry bees."

Here's a framework that works:

Step 1: Start With the Baseline

Pick your starting point from the big three — DC 10, 15, or 20. Ask yourself: "Would a trained professional struggle with this?"

• If no → DC 10
• If maybe → DC 15
• If yes → DC 20

Step 2: Adjust by Circumstance (±2 to 5)

Nudge the DC up or down based on conditions:

Lower the DC (−2 to −5) when:

• The character has relevant tools or resources
• They've done careful preparation
• Circumstances are unusually favorable
• Another character is helping (or just use advantage)

Raise the DC (+2 to +5) when:

• Conditions are hostile (darkness, noise, time pressure) - see our conditions guide for how status effects interact with checks
• The target is resistant or alert
• The task is more complex than it first appears
• There are compounding factors (doing two things at once)

Step 3: Sanity-Check With the Probability Table

Glance at the math table above. If your party's best bonus for this skill is +5 and you've set DC 22, that's a 20% chance. Is that the feeling you want? If you want tension but not futility, drop it to DC 18 or DC 19.

Contested Checks vs. Fixed DCs

Not every challenge needs a fixed DC. When a character is acting directly against another creature, use a contested check instead.

The grappling rules are a good example: the attacker rolls Athletics, and the target rolls Athletics or Acrobatics. Highest total wins. No DC needed.

Use contested checks when:

• Two creatures are directly opposing each other (arm wrestling, tug of war)
• Stealth vs. Perception (hiding from a specific creature)
• Deception vs. Insight (lying to someone's face)
• A creature is actively resisting (grapple, shove)

Use fixed DCs when:

• The challenge is environmental (climbing a wall, picking a lock)
• There's no active opposition (recalling lore, foraging for food)
• You want consistent difficulty regardless of who attempts it

Passive Checks and When to Use Them

Every character has passive scores: 10 + all modifiers that normally apply. Passive Perception (10 + Wisdom modifier + proficiency if applicable) is the most common.

Use passive checks when:

• You don't want the player to know a check is happening (noticing a hidden trap)
• The task is ongoing or repeated (keeping watch during a long rest)
• You want to avoid the "I roll Perception on everything" problem

A character with passive Perception 15 automatically notices anything with a Stealth result below 15. No roll, no announcement, no metagaming.

Group Checks: When the Whole Party Tries

When everyone attempts the same thing (sneaking past guards, climbing a cliff), use a group check. Everyone rolls. If at least half the group succeeds, the whole group succeeds.

This is elegant because it means the stealthy rogue can compensate for the clunky paladin. Set the DC where you'd normally set it — the group mechanic handles the rest.

Seven Mistakes GMs Make With DCs

1. Defaulting to DC 15 for Everything

DC 15 is medium difficulty, not default difficulty. If you use it for everything, your wizard's Intelligence doesn't feel different from the barbarian's. Vary your DCs to make character builds matter.

2. Setting DCs After the Roll

Players can tell. Even if you're trying to be generous, adjusting the DC after seeing the result erodes trust. Pick the number before the die hits the table. If you're not sure, DC 15 and commit.

3. Calling for Rolls on Trivial Tasks

The 20-Strength fighter can break a chair. The Druid with +9 Nature knows what poison ivy looks like. Proficiency and high stats should feel like superpowers for easy tasks. Save rolls for actual challenges.

4. Making Failure a Dead End

"You fail the check. Nothing happens." That's the worst outcome at your table — not because the character failed, but because the game stalled. Always have failure lead somewhere: a complication, a partial success, a new obstacle, or revealed information.

5. Ignoring Passive Scores

If a character has passive Perception 18 and the trap's Stealth DC is 14, they spot it automatically. Don't make them roll just because it would be more dramatic. Their investment in Wisdom earned them that.

6. Stacking Too Many Checks

"Roll Perception to notice the tracks, then Survival to follow them, then Nature to identify the creature." Three checks for one activity means three chances to fail. Combine related steps into a single check, or use the first check's result to inform the narrative without more dice.

7. Forgetting Advantage and Disadvantage

Before adjusting the DC by 3 points, consider whether the situation just warrants advantage or disadvantage instead. The player describing a creative approach? Grant advantage. Trying something while distracted? Disadvantage. It's simpler and more dramatic than tweaking numbers.

Quick Reference: DC by Skill

Here's a cheat sheet for the most commonly checked skills at each difficulty tier:

| Skill | DC 10 Example | DC 15 Example | DC 20 Example | |---|---|---|---| | Perception | Hear a conversation through a wooden door | Spot a hidden figure in dim light | Notice an invisible creature by sound | | Investigation | Search a room for obvious clues | Find a hidden compartment | Decode an encrypted message without a key | | Persuasion | Haggle 10% off with a friendly merchant | Convince a guard to bend a minor rule | Talk your way past a suspicious noble at court | | Stealth | Move quietly through tall grass | Sneak past a distracted sentry | Cross a creaky floor without alerting anyone | | Athletics | Climb a rough cliff face | Swim across a river with current | Hold a gate shut against an ogre | | Arcana | Identify a common spell | Recognize an unusual magical effect | Deduce the school of a custom spell from residue |

Need the full list of all 18 skills with their abilities? Check our Skill Check & DC Reference tool — it's free and searchable.

Putting It All Together

Setting DCs well comes down to three things:

1. Know the scale. Internalize the 5–10–15–20–25–30 ladder.
2. Read the room. Match the DC to the dramatic weight of the moment, not just the physical difficulty. This same instinct applies to balancing encounters - difficulty should serve the story.
3. Make failure interesting. The DC doesn't matter if both outcomes push the story forward.

The best GMs don't agonize over whether something is DC 14 or DC 16. They pick a number that feels right, commit to it, and make whatever happens next feel inevitable.

Your players won't remember the exact DC. They'll remember what happened when they rolled.

Try It in Action

StoryRoll is a free AI Game Master that handles DCs, skill checks, and dice rolls automatically — so you can focus on playing, not looking up rules.

The AI sets DCs based on the fiction, resolves checks instantly, and narrates the outcome. No prep. No rules lawyering. Just play.

Start a Free Quest →