CR for Simple Traps (5e Variant Rule)

CR for Simple Traps

"Okay, we made it past the hallway of pits, dodged under the swinging blades, held our breath through the chamber of gas and only just escaped with the treasure! Quite the experience for our adventuring party! Did we level up?"

"Eeeh, nope. 0 XP each."

In default play, simple traps in 5th edition do not grant experience points.

This variant rule treats simple traps like monsters for the purpose of assigning them a Challenge Rating. The principle is that a trap is not dissimilar to a monster: encountering one uses up party resources (such as hit points) and may require checks to overcome or bypass. Even an easy-to-spot-and-bypass simple pit trap can be given a CR value, much like an unthreatening monster like a rat is given a CR – ultimately the DM still decides whether or not to award the XP.

Traps with CR can also be used when building combat encounters, substituting some monsters for traps. When you do this, assume that the monsters know about the traps. If intelligent, monsters will use such traps to their advantage.

Calculating CR

The method presented in the Dungeon Master's Guide (p. 273) is used. Since a simple trap is "defeated" as soon as it is triggered (requiring a reset before it can trigger again), its Defensive CR is always 0. When determining Offensive CR, the average damage/round over 3 rounds is considered, so in most cases this will simply be the trap's damage divided by 3. If a trap automatically deals damage without an attack roll or saving throw, the DC of the check required to spot or investigate the trap is used. Some traps automatically reset, and are in principle able to trigger every round, but it is assumed that the players will avoid deliberating triggering it again.

Awarding XP

The XP for a trap is awarded if the trap is triggered, or if it is bypassed after being detected or disarmed. "Bypass" here means continuing to explore an area that the trap was meant to defend against. If the team spot a trap in one passageway and decide to go a different route, that is not overcoming the trap (similar to avoiding a hiding monster rather than sneaking past it or engaging).

Quick Traps

The Dungeon Master's Guide (p. 121) and Xanathar's Guide to Everything (p. 116) having tables for quickly assigning trap effects. The following table shows the CR for each entry in the "Damage Severity by Level" table.

By Attack Bonus

Character level	Moderate (+5)	Dangerous (+8)	Deadly (+12)
1–4	1/8	1/4	2
5–10	1/4	1	3
11–16	1/2	2	4
17–20	2	3	5

By Saving Throw

Character level	Moderate (DC 10)	Dangerous (DC 15)	Deadly (DC 20)
1–4	0	1/8	2
5–10	0	1/2	3
11–16	1/8	2	4
17–20	1/2	3	4

Simple Traps

These are the CRs for the simple traps published in *DMG* and *XGtE*.

Trap	CR	Source
Bear Trap	1/8	XGtE p. 114
Collapsing Roof	1	DMG p. 122
Crossbow Trap	1/4	XGtE p. 114
Falling Net	0	DMG p. 122
Falling Portcullis	0	XGtE p. 114
Fiery Blast	2	XGtE p. 114
Fire-Breathing Statue	1/2	DMG p. 122
Net Trap	0	XGtE p. 114
Pit Trap	0	XGtE p. 115
Poison Darts	2	DMG p. 123
Poison Needle	1	XGtE p. 115
Rolling Sphere	3	DMG p. 123
Scything Blade	1	XGtE p. 115
Sleep of Ages	2	XGtE p. 115
Sphere of Annihilation	2 or 31	DMG p. 123

¹ The CR depends on how the sphere is placed. If a victim can withdraw once damaged, it is CR 2. If the sphere is placed in such a way that a victim cannot easily withdraw (such as at the bottom of a pit, or subject to the sympathy effect noted in the DMG), it is CR 3.

5.00

(one vote)

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