Risk Priority Number (RPN) Calculator
Formula: RPN = Severity × Occurrence × Detection
What is Risk Priority Number (RPN)?
The Risk Priority Number (RPN) is a key metric used in Failure Mode and Effects Analysis (FMEA) to evaluate and prioritize potential risks in a process, product, or system. It helps identify which failure modes need immediate attention by quantifying risk based on three factors:
- Severity (S): Impact of the failure
- Occurrence (O): Likelihood of the failure happening
- Detection (D): Ability to detect the failure before it occurs
Each factor is rated from 1 to 10, and the RPN is calculated as:
RPN=Severity X Occurrence X Detection
RPN Rating Scale
| RPN Range | Risk Level | Action Recommendation |
|---|---|---|
| 1–100 | Low Risk | Monitor and document |
| 101–200 | Moderate Risk | Investigate and improve |
| 201–1000 | High Risk | Immediate corrective action |
How to Reduce RPN
To lower the Risk Priority Number:
- ✅ Redesign the process or product to reduce severity
- 📉 Use controls to reduce occurrence of failures
- 🔍 Improve inspections or detection methods to increase detectability
- 🔁 Update your FMEA regularly to reflect changes and new risks
