Quality & Six Sigma

Pareto Chart Calculator

Paste your defect or cost data, rank the categories from largest to smallest, and instantly visualise the Pareto principle — with descending bars, a cumulative percentage line, and the 80% threshold highlighted.

Principle
80% of effects come from 20% of causes

Enter your values

Enter each category and its count or cost on a new line, separated by a comma. Order doesn't matter — we'll rank them for you. Enter at least 2 rows in the format: category, value
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Ready to calculate

Enter your values on the left, then press Calculate.

Vital few
categories cause 80%
Total observations
Top category share
Cumulative cover at 80%
What this means

How it works

Understanding Pareto Chart

1

The 80/20 rule

The Pareto principle observes that for many phenomena, roughly 80% of effects come from 20% of causes. In quality and process improvement, that means a small number of categories typically drive the majority of defects, downtime or cost.

2

Why ranking matters

Sorting causes from largest to smallest, with a cumulative line drawn over the bars, instantly reveals where to focus. Tackling the first 2-3 bars usually delivers more than working through the rest of the list combined.

3

Quantity vs cost Pareto

A defect category that occurs often may not be the most expensive. It is often worth running two Paretos — one by frequency, one by cost — and combining the insights to pick the highest-value improvement target.