Dungeons & Dragons
Encounter CR calculator
Enter your party and how many fights you plan per long rest, and get a target total Challenge Rating to spend on monsters, plus how many monsters to use for each difficulty. Pick monsters whose CRs add up to the target.
3
target total CR
| Difficulty | Monsters | ~CR each |
|---|---|---|
| Easy | 0 | 0 |
| Moderate | 0 | 0 |
| Hard | 0 | 0 |
| Deadly | 0 | 0 |
Fewer planned fights per long rest means each one can be deadlier (the party can spend all its resources in one go); more fights means each must be easier (resources get ground down). Within a row, the CR budget stays the same - harder difficulties just split it across more monsters (more bodies = more actions).
How it works
The encounter calculator sizes a fight to your party. Enter how many players you have and their level, and it works out a target difficulty budget, then shows how many monsters of a given Challenge Rating make an easy, moderate, hard, or deadly encounter.
It runs entirely in your browser and stays edition-agnostic, so it works as a quick planning aid whether you are building a one-shot ambush or a boss fight. Use it to avoid the two classic mistakes: a "tough" fight the party steamrolls, or a "minor" fight that nearly kills someone.
Example. For four level-5 characters, the calculator sets the difficulty thresholds, then tells you that a single high-CR monster lands around hard while a swarm of weak ones can tip into deadly.
FAQ
How is encounter difficulty calculated?
It builds a difficulty budget from party size and level, then compares your chosen monsters against the easy, moderate, hard, and deadly thresholds for that party.
Does it work for both 2014 and 2024 rules?
It is intentionally edition-agnostic and aimed at a quick budget. Use it as a planning guide, then sanity-check against your group, since real difficulty also depends on terrain, tactics, and resources.
Why was my 'easy' fight so dangerous?
Action economy matters: many weak monsters get many turns and can gang up. The calculator flags when monster numbers push the difficulty up, even if each one is individually weak.
What is a Challenge Rating (CR)?
Challenge Rating is the rough power level a monster is designed for: a lone CR 3 creature should be a fair fight for four level-3 characters. The calculator uses CR as the currency of its budget, telling you how many monsters of a given CR fit each difficulty tier for your party.