5e Random Encounter Generator

How the 2024 XP budget works

The 2024 rules size a fight with a simple budget. Each character gets an amount of XP based on their level and the difficulty you want, and you add those amounts up for the whole party. Then you spend that budget on monsters, using each monster’s XP value, without going over. There is no multiplier for the number of monsters any more.

A worked example: four level 5 characters at Moderate difficulty get 750 XP each, so the budget is 3,000 XP. One CR 5 monster (1,800 XP) plus two CR 2 monsters (450 XP each) comes to 2,700 XP, which fits. Add a third CR 2 monster and you are at 3,150, over budget, so the generator would drop it or swap it for something smaller.

The three difficulty levels are Low, Moderate and High. Low is a fight the party should win while spending a few resources. Moderate costs real hit points and spell slots. High can drop a character or two if the dice go badly. If you want to check a fight you built by hand, the encounter calculator shows the full budget table and where your monsters land.

The monsters come from the free SRD 5.2. The SRD doesn’t say where monsters live, so the environment tags (Arctic, Coast, Desert, Forest, Grassland, Hill, Mountain, Swamp, Underdark, Underwater, Urban, Dungeon and Planar) are our own classification. Expect some judgement calls, like a creature that turns up in both Forest and Hill.

Why many weak monsters hit harder than the maths says

The budget treats XP as if it adds up evenly, but action economy doesn’t. Eight monsters get eight turns per round, and eight chances to land a hit, impose a condition or drag someone down. Four characters facing eight goblins spend most of a fight just reaching them.

Low-level parties feel this most, because a level 1 character can drop from two hits. If the generator hands you a big pack, consider running it at Low or Moderate even when you planned High, or bring some of the pack in as a second wave a couple of rounds later. Area spells cut the other way: a well-placed fireball can make a horde fight much easier than its XP suggests.

Changing difficulty without changing monsters

The same group of monsters can be a walkover or a nightmare depending on where you put them.

• Give the monsters cover, height or a choke point and the fight gets harder. Open ground with nowhere to hide favours the side with more ranged attacks.
• Add an objective. Protecting a cart, closing a portal in three rounds or reaching the far side of a bridge pulls the party apart and makes a Low encounter feel High.
• Let monsters flee or surrender at half strength. A fight doesn’t need to end in a pile of bodies, and morale makes the world feel alive.

Random encounters vs planned ones

A planned encounter carries the story: the boss in the tower, the ambush the villain set up. A random encounter makes the world feel like it continues without the party. The situation hook the generator adds, such as monsters arguing over a kill or a camp being packed up, gives you a reason for the fight and often a way to avoid it. Use it. A random fight the players can talk their way out of is more memorable than one they grind through.

Keep random encounters mostly at Low or Moderate. They should cost resources and create tension on a journey, not end a campaign over a bad roll on the road.

How often to roll on the road

There is no single right rate, but this is a good starting point. Roll a d20 once per day of travel and once per night. On an 18 or higher, something happens. That gives roughly one encounter every three days, which keeps a long journey from turning into a string of fights.

Raise the chance in dangerous country (a 15 or higher in a haunted forest) and lower it on patrolled roads. Not every result needs to be a fight; a hit can be tracks, a ruined camp or a travelling merchant. The NPC generator is handy for the peaceful ones, and when a fight does end, the loot generator covers what the monsters were carrying.