FMEA Risk Priority Number
Multiplies the three FMEA scores into a risk priority number: severity times occurrence times detection, each 1 to 10, product 1 to 1000.
Open the tool → Runs in your browser. Data leaves only if you deliberately send a problem report from the interactive tool.
Example
- Severity, a whole number 1 to 10
- 10
- Occurrence, a whole number 1 to 10
- 5
- Detection, 1 to 10, where 1 is almost certain to be caught
- 2
Result: a risk priority number of 100, reported without a band
The tool opens with these values already filled in. Replace them with your own.
What the result means
- The arithmetic
- Severity times occurrence times detection, each scored 1 to 10, so the product runs 1 to 1000.
- Detection
- Scored backwards from the other two: 1 is almost certain to be caught, 10 is almost impossible.
- It does not rank
- A product collapses three questions into one. 10 x 5 x 2 and 2 x 5 x 10 both come to 100, and only one of them is dangerous.
- Severity alone
- A severe failure mode stays severe however rare it is and however well it is caught, whatever the product comes to.
- No threshold
- Acting above 100 is a local convention and appears in no standard, which is why nothing here is banded.
- Superseded
- The 2019 AIAG-VDA revision replaced the risk priority number with an Action Priority, for these reasons.
What you enter
- Severity, a whole number 1 to 10
- Occurrence, a whole number 1 to 10
- Detection, 1 to 10, where 1 is almost certain to be caught
How this is calculated
International Electrotechnical Commission. IEC 60812: Failure modes and effects analysis (FMEA and FMECA). 3rd ed. Geneva: IEC; 2018. Successor: AIAG-VDA FMEA Handbook, 1st ed. 2019, which replaced the risk priority number with an Action Priority. Read the source ↗
A reference and educational tool. Not medical, legal, or financial advice, and not a substitute for clinician judgment.