How to make a Pareto chart
- Copy the category column. If there is a separate quantity or amount per category, copy that column too.
- Paste into the data table (paste on a column header to use the first line as column names).
- Choose the X-axis (category) column, and either leave Y at '(Count)' or choose a value column to sum.
- Press Draw and check which items fall within the cumulative 80% and the automatic interpretation.
What is a Pareto chart?
A Pareto chart shows category sizes as bars sorted from largest to smallest together with a line of their cumulative percentage. Based on the Pareto principle - roughly 80% of effects come from 20% of causes - it is one of the seven basic quality tools for finding the vital few causes to fix first.
It is the first chart to reach for when deciding where to focus: defects by type, downtime by failure cause, or customer complaints by category.
Counting vs summing values
With Y at '(Count)', the tool counts how many times each item appears in the category column (records where each row is one defect). Choose a value column to sum that value per item (tables with a quantity, amount or time per item).
How to read a Pareto chart
- The items up to where the cumulative line crosses the dashed 80% line are the top priorities.
- If the top 30% of items or fewer account for 80% of the total, the data follow the Pareto principle.
- If the bars are all of similar height, many causes contribute evenly rather than a few dominant ones.
Frequently asked questions
What should the data look like?
For records where each row is one defect, one category column is enough ('(Count)'). For a summary table with a quantity per item, paste the item and quantity columns and choose the quantity column as Y.
What if the same item appears in several rows?
Rows with the same item name are combined into one bar automatically.
What is the dashed 80% line?
It is the threshold of the Pareto (80/20) principle. The items before the cumulative line crosses it are the key items that make up most of the total.
Is my data sent to a server?
No. Everything is processed inside your browser and nothing is transmitted or stored.
Other chart tools
Need process capability, control charts or DOE?
The Qstat desktop program offers about 250 analysis features: histograms and box plots plus process capability (Cp, Cpk), control charts, measurement system analysis (MSA), design of experiments (DOE), regression and machine learning.
Try Qstat free for 30 days