FMEA Risk Priority Number Calculator

Work out fmea risk priority number instantly with clear inputs, formula shown and shareable results.

About FMEA Risk Priority Number Calculator

RPN is severity x occurrence x detection, each rated 1 to 10. Its weakness is that very different risk profiles give the same product, so severity 9 or 10 items must trigger action regardless of RPN, and criticality (severity x occurrence) is reviewed alongside it. Newer FMEA standards replace RPN with an action priority table for this reason.

Formulas

Risk priority number

RPN = severity x occurrence x detection

Criticality

Criticality = severity x occurrence

Worked example

With the default values below, FMEA Risk Priority Number Calculator returns Risk Priority Number of 192. Change any input above and every figure here is recalculated in your browser.

Inputs used

Severityaccepts 1–10: 8
Occurrenceaccepts 1–10: 4
Detectionaccepts 1–10: 6
Action Threshold RPNminimum 1: 100

Results

Risk Priority Number: 192
Criticality (severity x occurrence): 32
Action Priority: High - above action threshold
Amount Above Threshold: 92

Step by step

1Values used
2Risk priority number
3Criticality
4Risk Priority Number= 192
5Criticality (severity x occurrence)= 32
6Action Priority= High - above action threshold
7Amount Above Threshold= 92

Assumptions and limits

The result is derived only from the 4 inputs listed above. Anything not among them is not part of the calculation.
In particular, this calculator does not take inflation, tax, fees or charges or compounding frequency into account.
Figures are rounded for display to whole numbers, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.
FMEA for safety-critical or regulated products must follow the applicable standard and be reviewed by qualified engineers. Severity 9 and 10 failure modes require action irrespective of any numerical score.

How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.

FMEA for safety-critical or regulated products must follow the applicable standard and be reviewed by qualified engineers. Severity 9 and 10 failure modes require action irrespective of any numerical score.

Frequently Asked Questions

Why is RPN criticised?

A 10-1-1 risk and a 1-10-10 risk both score 100, yet the first can injure someone and the second cannot. RPN thresholds alone therefore mis-prioritise safety-related failure modes.

Which lever should be improved first?

Reduce occurrence by design or process change wherever possible. Improving detection only catches the failure after it happens and adds inspection cost without preventing anything.