Pareto Analysis Calculator
Rank up to ten categories by count with shares and cumulative share.
What this calculator does
Sort descending, divide each count by the total, accumulate. The number of categories making up the first 80% is reported as a reading aid.
Inputs and what they mean
- Category 1
- — text value.
- Count 1
- — Defects, complaints, downtime minutes or cost — one consistent measure across all categories..
- Category 2
- — text value.
- Count 2
- — Defects, complaints, downtime minutes or cost — one consistent measure across all categories..
- Category 3 (optional)
- — text value.
- Count 3 (optional)
- — Optional. Leave at 0 to exclude it from the result. A category counted as 0 is left out of the chart..
- Category 4 (optional)
- — text value.
- Count 4 (optional)
- — Optional. Leave at 0 to exclude it from the result. A category counted as 0 is left out of the chart..
- Category 5 (optional)
- — text value.
- Count 5 (optional)
- — Optional. Leave at 0 to exclude it from the result. A category counted as 0 is left out of the chart..
- Category 6 (optional)
- — text value.
- Count 6 (optional)
- — Optional. Leave at 0 to exclude it from the result. A category counted as 0 is left out of the chart..
- Category 7 (optional)
- — text value.
- Count 7 (optional)
- — Optional. Leave at 0 to exclude it from the result. A category counted as 0 is left out of the chart..
- Category 8 (optional)
- — text value.
- Count 8 (optional)
- — Optional. Leave at 0 to exclude it from the result. A category counted as 0 is left out of the chart..
- Category 9 (optional)
- — text value.
- Count 9 (optional)
- — Optional. Leave at 0 to exclude it from the result. A category counted as 0 is left out of the chart..
- Category 10 (optional)
- — text value.
- Count 10 (optional)
- — Optional. Leave at 0 to exclude it from the result. A category counted as 0 is left out of the chart..
How to use it
- Enter your own figures — the calculator never fills in a rate, price or benchmark for you.
- Press Calculate to see the result.
- Read the formula, variables, assumptions and source below the result before you rely on it.
Formula
Share_i = (Count_i ÷ Σ Count) × 100; Cumulative_i = (Σ_{j≤i} Count_j ÷ Σ Count) × 100, categories sorted from largest to smallest
Worked example
Five defect categories ranked
Ranked by count, with each category's share and the running cumulative share.
Reading the result
The headline figure is the main answer. Any breakdown underneath shows the parts that make it up, so you can check the working and see what changes when you adjust an input.
Limitations and assumptions
Results depend entirely on the figures you enter and are rounded for display. They are for general information and education, not professional advice.
Reference: American Society for Quality — Process capability and defect rate measures
Last reviewed:
Common questions
Formula, source and verification
Categories are sorted by count, each share is expressed against the total, and the cumulative share is accumulated down the ranking.
The question it answers: How much of our output is right first time, and how much survives every step?
The formula
Share_i = (Count_i ÷ Σ Count) × 100; Cumulative_i = (Σ_{j≤i} Count_j ÷ Σ Count) × 100, categories sorted from largest to smallest
- Count_i — Category count
- (count). Defects, complaints, downtime or cost for one category — one consistent measure across all categories.
- Σ Count — Total
- (count). Sum of the categories entered.
Units: One consistent measure in; percentages out.
What kind of calculation this is
Deterministic formula. The same inputs always give the same answer. The maths is fixed and does not depend on judgement.
Method
Sort descending, divide each count by the total, accumulate. The number of categories making up the first 80% is reported as a reading aid.
Assumptions built into the result
- Mathematical: All categories are measured on the same scale.
- Mathematical: Categories do not overlap.
Figures this calculator will never guess for you
- No benchmark, target or 'world class' value is supplied or implied; the result describes only the figures entered.
- The 80/20 pattern is not assumed — the cumulative share is reported from the entered counts, whatever it turns out to be.
- No cause, priority or corrective action is inferred from the ranking.
Limitations
- Ranking by count treats every occurrence as equally important; a rare but severe category will rank low.
- The result depends entirely on how the categories were defined.
- Arithmetic over the counts entered — it cannot tell whether the inspection behind them was complete or consistent.
Source and version
- Standard or reference
- Pareto chart — ASQ (ASQ quality resources, Pareto chart: categories are ordered by frequency with a cumulative percentage line.)
- Published source
- American Society for Quality — Quality resources
- Formula version
- Version 1
- Verification
- Reviewed against the cited source on
- How much weight the source carries
- Standards or government
- Applies to
- Currency
- The result is a ratio or index, so it does not depend on currency.
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