Use this tool to quickly calculate the Challenge Rating (CR) of your custom monster or encounter in the Pathfinder Roleplaying Game (1st Edition). Input the estimated Defensive CR and Offensive CR values to find the final, balanced CR.
Pathfinder CR Calculator
Pathfinder CR Calculator Formula
The Challenge Rating (CR) for a Pathfinder creature is a complex value, typically calculated by averaging its Defensive CR (DCR) and Offensive CR (OCR) and applying a final adjustment.
Formula Sources: Archives of Nethys (Official Rules), Monster Advancement Rules (CR tables)
Variables
- Defensive CR (DCR): A value derived from a creature’s defensive capabilities, primarily Hit Points (HP), Armor Class (AC), and saving throws (Fort, Ref, Will). Higher DCR indicates a harder creature to kill.
- Offensive CR (OCR): A value derived from a creature’s offensive output, primarily attack bonus, damage per round (DPR), and spell save DCs. Higher OCR indicates a higher threat to players.
- CR Adjustment Factor (ADJ): An optional numerical adjustment (usually ±0.5 or ±1.0) applied for unusual abilities, specific weaknesses, or unique environmental factors not captured by DCR/OCR.
Related Calculators
- Pathfinder Initiative Tracker
- Average Damage Per Round (DPR) Calculator
- Base Attack Bonus (BAB) Calculator
- Monster XP Value Generator
What is Challenge Rating (CR)?
Challenge Rating (CR) is a key metric in the Pathfinder Roleplaying Game (and similar systems) designed to measure the difficulty of a monster or hazard. A monster’s CR is intended to be equal to the level of a party of four balanced adventurers who should be able to defeat that creature in a fair fight, losing only a small amount of resources.
The system is used by Game Masters (GMs) to create balanced encounters. For example, a single monster with CR 5 is considered an average challenge for a party of four 5th-level characters. Understanding DCR and OCR is crucial because a creature might be extremely tough (high DCR) but deal little damage (low OCR), or vice versa, leading to a final CR that balances these two aspects.
How to Calculate Pathfinder CR (Example)
- Determine Defensive CR (DCR): Based on its total HP, AC, and saving throws, the GM estimates the creature’s DCR. Let’s assume a powerful Golem has a DCR of 8.0.
- Determine Offensive CR (OCR): Based on its primary attack routine (e.g., slam attacks and breath weapon), the creature’s average damage per round and attack modifiers lead to an estimated OCR of 7.0.
- Check for Adjustments (ADJ): The Golem has a special, immediate-use ability that is not fully captured by its offensive stats. The GM applies a +0.5 ADJ.
- Apply the Formula: $\text{CR}_{\text{Interim}} = (\text{DCR} + \text{OCR}) / 2 = (8.0 + 7.0) / 2 = 7.5$.
- Final Calculation: $\text{CR}_{\text{Final}} = 7.5 + 0.5 (\text{ADJ}) = 8.0$. The final Challenge Rating is 8.
Frequently Asked Questions (FAQ)
What is the difference between DCR and OCR?
DCR (Defensive Challenge Rating) measures how hard a creature is to kill or affect, focusing on HP, AC, and Saves. OCR (Offensive Challenge Rating) measures how much of a threat the creature poses to the party through its attacks and abilities.
Why is the final CR rounded?
Challenge Ratings are whole numbers (or occasionally half-steps in some systems) for ease of use. The rounding function ensures the final result is practical for encounter building, reflecting the nearest level of difficulty.
Can I use negative adjustments in the ADJ field?
Yes. A negative adjustment (e.g., -1.0) is appropriate for creatures with severe, easily exploitable weaknesses, such as vulnerability to a common element or limited offensive range.
What is the maximum CR?
While there is technically no hard limit, the official Pathfinder bestiaries generally cap at CR 30, and encounters beyond this are extremely rare and highly challenging for even the highest-level parties.