Random Encounter Generator

Enter your party's levels, pick a difficulty and get a ready-to-run fight built from the 330 creatures in the open SRD 5.2.1, sized to the SRD XP budget. Not quite right? Re-roll, or send it to the encounter calculator to tweak it. Runs in your browser; nothing is uploaded.

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How it builds a fight

It follows the combat encounter steps in the SRD 5.2.1:

  1. Budget. Each character adds their XP budget for the chosen difficulty (for example 50 XP for Low, 75 for Moderate and 100 for High at level 1), and the party total is the budget.
  2. Spend it. It picks one to three kinds of creatures and spends as much of the budget as it can without going over, keeping the total above the next-easier budget so the fight really rates at the difficulty you chose.
  3. Keep it runnable. At most three stat blocks, no CR 0 creatures, no more than two creatures per character, and by default no creature whose CR is above the party's average level, since the SRD warns those can take out a character with one action.

Want the same kind of foe every time? Pick a creature type, such as Undead or Beast, for a themed fight. To hand-pick monsters, use the monster finder; for a ready-made first adventure, try a free one-shot. Track the fight on paper with the printable initiative tracker.

Where the numbers come from

XP budgets per character come from the XP Budget per Character table and monster CR, XP, AC and HP from the stat blocks in the System Reference Document 5.2.1 (CC-BY-4.0). Difficulty is a guide, not a promise: dice, tactics and terrain can make any fight easier or harder. Checked Oct 30, 2026.

FAQ

How does the random encounter generator decide difficulty?

It adds up each character's XP budget for the chosen difficulty from the SRD 5.2.1 table, then picks monsters whose total XP fits under that budget but above the next-easier one.

Can I make a fight with only one kind of monster?

Yes. Set Kinds of monsters to 1 kind, or pick a creature type for a themed fight.

Why doesn't it use monsters stronger than my party?

The SRD 5.2.1 warns that a creature whose CR is higher than the party's level might take out a character with a single action. Tick the box to allow them anyway.

Is it free?

Yes. It runs in your browser with no sign-up.