What is a Pareto chart?
A Pareto chart combines a sorted bar chart with a cumulative percentage line. The bars rank problem categories from the most to the least frequent (or costly); the line shows how much of the total is explained as you move from left to right. It is one of the seven basic quality tools and the standard way to decide where to focus first.
How to read a Pareto chart
- Left axis: the count or cost of each category.
- Right axis: the same scale expressed as a percentage of the total, used to read the cumulative line.
- Where the line crosses the cut-off (often 80%), everything to the left is the vital few.
- A flat Pareto, where bars are similar in height, means the categories are too broad, or the data should be stratified another way.
Pareto chart example
The example ranks 137 customer complaints from one quarter. By count, late delivery, damaged packaging, wrong item shipped and missing documentation make up 84% of complaints. Switch to Cost and the picture changes: product defects, only 9 complaints, are the most expensive category at $16,650, followed by wrong items shipped. The two views lead to different priorities, which is why it is worth checking both.
Tips for better Pareto analysis
- Use consistent categories and a defined period, ideally collected with a check sheet.
- Drill down: make a second-level Pareto of the biggest bar (for example, late deliveries by carrier).
- Compare before and after an improvement using the same categories and scale.
- Then find the cause of the top bar with a fishbone diagram or 5 Whys.
How to use this Pareto Chart tool
- Enter categories and counts. Type or paste your categories and how often each occurred, for example from a check sheet or your complaint log.
- Add costs (optional). Enter the cost per occurrence if you want to rank by cost impact instead of frequency.
- Read the chart. Bars are sorted automatically and the cumulative line shows how much of the total the top categories explain.
- Identify the vital few. Categories reached before the cut-off (80% by default) are highlighted as the vital few.
- Group the trivial many. Optionally merge small categories into "Other" to keep the chart readable.
- Act and export. Start root cause analysis on the vital few, and export the chart for your report.
Frequently asked questions
What is a Pareto chart?
A Pareto chart is a bar chart with the categories sorted from largest to smallest, combined with a line showing the cumulative percentage. It shows at a glance which few categories account for most of the problem.
What is the 80/20 rule?
The Pareto principle, named after economist Vilfredo Pareto and applied to quality by Joseph Juran, observes that roughly 80% of the effects come from 20% of the causes. The exact split varies, but quality problems are almost always concentrated in a "vital few" categories.
How do I make a Pareto chart?
List the categories and their counts (or costs), sort them from largest to smallest, calculate each category's percentage of the total and the running cumulative percentage, then plot the bars and the cumulative line. This tool does all of that automatically as you type or paste your data.
Should a Pareto chart use counts or cost?
Both are useful. Frequency shows what happens most often; cost (or severity) shows what hurts most. A defect that is rare but expensive can matter more than a frequent cosmetic one, so check both. Switch between Count and Cost in this tool.
What should go in the "Other" category?
Group small categories into "Other" to keep the chart readable, and always show it as the last bar regardless of its size. If "Other" becomes one of the largest bars, break it down into more specific categories.
Can I export the Pareto chart to Excel?
Yes. Export the ranked Pareto table and your data to Excel or CSV, the chart to PNG, or a PDF report. It is free with no sign-up.