Failure Cause Analyzer Calculator

Turn defect logs into clear, decision-ready insights quickly. Use 6M categories and risk priorities easily. Compare batches, download summaries, and fix root causes now.

Failure Input

Add multiple failure rows, then analyze to rank causes and build a Pareto focus list.
Auto mode scales occurrence using each row’s share of total.
Used to calculate overall PPM (Failures / Units × 1,000,000).
Rows meeting this threshold are highlighted in results.

Failure Rows

Reset
Row 1
Severity, Occurrence, Detection are 1 (best) to 10 (worst).
Used only when manual mode is selected.
Estimate scrap, rework, warranty, or downtime cost.
This field is not stored or exported.
Row 2
Severity, Occurrence, Detection are 1 (best) to 10 (worst).
Used only when manual mode is selected.
Estimate scrap, rework, warranty, or downtime cost.
This field is not stored or exported.
Row 3
Severity, Occurrence, Detection are 1 (best) to 10 (worst).
Used only when manual mode is selected.
Estimate scrap, rework, warranty, or downtime cost.
This field is not stored or exported.
Tip: Start with last 30 days of defects for stable ranking.

Example Data

Use this as a reference structure. The “Load Example Data” button fills the form automatically.
Failure Mode Cause 6M Count Sev Det Cost/Failure
Seal leak Incorrect gasket seating Method 18 8 6 4.50
Surface scratch Worn conveyor rollers Machine 34 5 4 1.20
Loose connector Under-torque at station Man 12 7 5 3.10
Dimensional drift Gauge not calibrated Measurement 7 6 7 2.75
Contamination High humidity in storage Environment 9 6 6 1.90

Formula Used

  • Risk Priority Number (RPN): RPN = Severity × Occurrence × Detection
  • Share of failures: Share% = (Row Count ÷ Total Count) × 100
  • Pareto cumulative share: cumulative sum of Share% after sorting by RPN.
  • Overall PPM: PPM = (Total Failures ÷ Inspected Units) × 1,000,000
  • Cost impact: Row Cost = Count × Cost per Failure
Auto occurrence rating scales from 1–10 using the row’s share of total failures.

How to Use This Calculator

  1. Enter inspected units if you want an overall PPM result.
  2. Add one row per failure mode and root cause.
  3. Choose Auto occurrence (from counts) or Manual occurrence (1–10).
  4. Set Severity and Detection ratings from 1 (best) to 10 (worst).
  5. Click Analyze Failures to rank and highlight risks.
  6. Download CSV or PDF to share actions and track improvements.

Risk scoring that stays comparable

This calculator uses Severity, Occurrence, and Detection ratings on a 1–10 scale, producing an RPN by multiplying the three values. Keeping the same rating rules across shifts makes trends meaningful. For example, a severity 8 leak that is hard to detect (7) will stay visible even if its count drops. Align scoring with your FMEA definitions and review outliers weekly to avoid “rating drift”.

Pareto focus from defect counts

After you enter failure counts, the tool computes each cause’s share of total defects and a cumulative share for quick Pareto review. A common target is the first set of causes that reaches about 80% of failures. This prevents teams from spreading effort across dozens of low-impact issues. Add data by product, station, or supplier to see whether the same causes repeat. When multiple shifts report defects, standardize counting rules and time windows to reduce noise in the overall Pareto.

PPM and cost impact for management reporting

If you enter inspected units, the calculator reports overall PPM using the standard multiplier of 1,000,000. That allows comparison between lines with different volumes. Optional cost per failure converts counts into estimated financial impact, covering scrap, rework labor, returns, and downtime. A medium-RPN issue with high volume can exceed a critical RPN issue with rare occurrence. Use cost to justify containment versus redesign decisions.

6M categorization for root-cause direction

Each row includes a 6M category (Man, Machine, Method, Material, Measurement, Environment). This classification helps you route investigations to the right owners and tools. A Machine cluster may trigger preventive maintenance, while a Measurement cluster suggests gauge R&R or calibration checks. Over time, category totals show whether systemic fixes are working. For mixed causes, duplicate rows to keep accountability clear.

Using exports to close the loop

CSV export supports deeper analysis, such as control charts, cost rollups, or linking to CAPA tracking. The PDF report is useful for audits and daily tier meetings because it summarizes top risks and key metrics on one page. Set an RPN highlight threshold to match your quality plan, then track whether targeted actions push items below that line. Re-export after actions to document improvement.

FAQs

1. How is RPN calculated in this analyzer?

RPN is computed as Severity × Occurrence × Detection. Higher values indicate higher risk because impact is severe, failures are frequent, and controls are weak. Use the ranking to decide where corrective action will reduce risk fastest.

2. What is the difference between Auto and Manual occurrence rating?

Auto mode derives occurrence from each row’s share of total failures, scaling from 1 to 10. Manual mode lets you enter occurrence directly when you follow a predefined FMEA table or have reliability data.

3. Why should I enter inspected units?

Inspected units enables an overall PPM calculation: (Total Failures ÷ Inspected Units) × 1,000,000. This normalizes performance across different production volumes and helps compare lines, shifts, or suppliers.

4. How does the Pareto list work here?

After sorting by RPN, the tool computes each cause’s share of total defects and a cumulative share. The Pareto set is the first group of causes that reaches about 80% cumulative share, highlighting the few issues driving most defects.

5. What does the RPN highlight threshold do?

Any row with RPN at or above your target threshold is highlighted in the results table. Set it to match your control plan, customer requirements, or internal escalation rules so reviewers can spot urgent items instantly.

6. What should I put in Cost per Failure?

Enter an estimated per-defect cost such as scrap, rework labor, retest time, warranty reserve, or downtime minutes converted to currency. The calculator multiplies this by the defect count to estimate row cost and total cost impact.

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Important Note: All the Calculators listed in this site are for educational purpose only and we do not guarentee the accuracy of results. Please do consult with other sources as well.