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FMEA RPN calculator: severity × occurrence × detection
Rate severity, occurrence and detection on a 4, 5 or 10-level scale and get the RPN against your action threshold (IEC 60812). Free, no sign-up.
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- On desktop and phone
Result
120Risk priority S × O × D
- Action required
- Yes
- Scale maximum
- 1,000
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What is FMEA?
FMEA (failure modes and effects analysis) is a structured, bottom-up method that lists the ways each part of a system can fail, the effect of each failure on the system and its causes. IEC 60812:2018 describes the method; when the failure modes are also ranked by criticality, the analysis is called FMECA. The usual ranking multiplies three ratings, severity, occurrence and detection, into a risk priority number (RPN).
Applied to equipment, an FMEA shows the maintenance team where preventive work pays for itself. A mode with a high RPN gets a periodic inspection, a sensor or a design change; one with a low RPN can be left to run to failure. The analysis is never finished once and for all: after each corrective action, or when the breakdown history contradicts a rating, the mode is rated again and its RPN moves.
From 1 to 1,000
On 1 to 10 scales the RPN runs from 1 to 1,000. Two very different modes can share a number: 10 × 2 × 5 and 2 × 5 × 10 both give 100, so read the severity before the product.
Action priority (AIAG and VDA)
The FMEA Handbook published by AIAG and VDA in 2019 replaces the RPN with an action priority, high, medium or low, read from tables that weigh severity first, then occurrence, then detection.
The 2018 edition of IEC 60812
Its third edition, published in August 2018, replaced the 2006 text and added alternative means of calculating risk priority numbers.
Equipment FMEA in maintenance
On machines already in service, the method runs function by function: what the machine must do, how it can stop doing it, and what the operator or the sensor would notice.
Reference documents : IEC 60812:2018, Failure modes and effects analysis (FMEA and FMECA) ; AIAG and VDA, FMEA Handbook (2019)
Each RPN filed with the machine's work orders
Here, the calculator is free and the result is gone when you close the page. In Reglova, it is attached to the work order on the right machine: you find it again at the next breakdown, and on audit day.
The CMMS software comparison, our gaps included- Attached to the work order with its inputs: the server recalculates it, it stays verifiable.
- On the technician's phone, even without a network.
- In the machine's history, for the next breakdown.
When to rate failure modes in an FMEA
01
Rank a machine's failure modes to decide where preventive maintenance should go.
02
Check that a corrective action has brought a mode below the threshold.
03
Compare ratings made with different scales (4, 5 or 10 levels).
Good to know
The number is only as good as the scale behind it: write down what each rating means (a stop of more than 4 hours, one failure a month…) before rating. A maximum severity often calls for action whatever the number.
Risk priority number: S × O × D and its scales
In an FMEA, each failure mode gets three ratings: its severity S, its occurrence O and its detection D, the likelihood that it goes undetected. Their product, the risk priority number, ranks the modes and points to those that require action. The calculation follows IEC 60812.
Formula · Reference documents
RPN = S × O × D
IEC 60812:2018
Inputs and accepted ranges
| Input | Unit | Accepted range | Example |
|---|---|---|---|
| Rating scale | 3 options | 1 to 10 | |
| Severity S | 1 to 10 | 8 | |
| Occurrence O | 1 to 10 | 5 | |
| Detection D | 1 to 10 | 3 | |
| Action threshold | 1 to 1,000 | 100 |
Calculated results
- Risk priority S × O × D
- Action required
- Scale maximum
From FMEA action to preventive plan in Reglova
- Breakdowns reported by QR code
- Work orders on the phone, even without a network
- Mandatory inspections reminded by email
- Audit file as a PDF, in one click
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