Advanced Analysis
FMEA / RPN Calculator
Failure Mode and Effects Analysis — rate severity, occurrence, and detection, rank failure modes by RPN, and prioritise corrective actions.
RPN = S × O × DRating Scale (1-10)
Severity: 1=None → 10=Hazardous
Occurrence: 1=Unlikely → 10=Very High
Detection: 1=Certain → 10=Impossible
Failure Mode #1
What is FMEA?
Failure Mode and Effects Analysis (FMEA) is a systematic methodology for identifying potential failure modes, their causes, and effects. It uses the Risk Priority Number (RPN) to prioritize which failures need corrective action first.
Risk priority number
RPN = Severity × Occurrence × DetectionRating scales
| Rating | 1 | 5 | 10 |
|---|---|---|---|
| Severity (S) | No effect | Moderate | Hazardous without warning |
| Occurrence (O) | Nearly impossible | Moderate | Very high (> 1 in 2) |
| Detection (D) | Almost certain detection | Moderate | No detection possible |
RPN ranges from 1 (lowest risk) to 1000 (highest risk).
RPN action thresholds
| RPN range | Risk level | Required action |
|---|---|---|
| 200 – 1000 | Critical | Immediate corrective action required |
| 120 – 199 | High | Corrective action should be prioritized |
| 80 – 119 | Medium | Plan corrective action |
| 1 – 79 | Low | Monitor — action may not be required |
Thresholds are organisation-specific; these are common defaults. Whatever the RPN, a failure mode with severity 9–10 deserves attention on its own.
Frequently asked questions
What are the types of FMEA?
Design FMEA (DFMEA) focuses on product design failures. Process FMEA (PFMEA) focuses on manufacturing process failures. System FMEA analyzes complete systems. IATF 16949 requires both DFMEA and PFMEA for automotive suppliers.
Is RPN still the best way to prioritize risk?
The AIAG-VDA FMEA handbook (2019) moved away from RPN to an Action Priority (AP) table that considers severity first. However, RPN remains widely used and is still a valid risk ranking tool for most industries.