Find the few causes, customers or products that make up most of the total. Paste categories and values, and the tool sorts them, draws a Pareto chart with a cumulative percentage line, and tells you how many categories it takes to reach 80%.
Last updated:
Use Label, 120, Label: 120 or paste two columns from a spreadsheet. Repeated labels are added together; a header row is skipped.
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How to use the Pareto Analysis Tool (80/20)
Enter your data: one category per line with its value, such as Late delivery, 42, or paste two columns from Excel or Google Sheets.
Name the values (Defects, Revenue ($), Units sold) so the chart axis and summary read correctly.
Set the cutoff: 80% is the classic rule, but you can use 70% or 90% to match your goal.
Read the results: the dark green bars are the vital few that reach the cutoff, the orange line shows the running total, and the table lists each category's share and ABC class.
Download the PNG or CSV for a report, quality review or slide.
How a Pareto analysis is calculated
Total the values of all categories.
Sort the categories from largest to smallest (a catch-all "Other" goes last).
Share of each category = value ÷ total × 100.
Cumulative % = (this value + all values above it) ÷ total × 100.
Vital few = the first categories needed for the cumulative % to reach the cutoff (usually 80%).
Worked example using the default defect data (376 defects in total):
Rank
Cause
Defects
% of total
Cumulative
Cumulative %
1
Scratched surface
142
37.8%
142
37.8%
2
Misaligned label
96
25.5%
238
63.3%
3
Loose screw
58
15.4%
296
78.7%
4
Dented panel
31
8.2%
327
87.0%
5–9
Five smaller causes
49
13.0%
376
100%
Four of nine causes (44%) are needed to pass 80%, and the top two causes (22% of the categories) already explain 63% of all defects, so fixing scratches and label alignment first gives the biggest improvement.
Where to use the 80/20 rule
Area
Categories
Value to measure
Typical question
Quality control
Defect or complaint causes
Count or cost of defects
Which few causes should we fix first?
Sales
Customers or accounts
Revenue or profit
Which customers deserve the most attention?
Inventory
Products or SKUs
Annual sales value
Which items need tight stock control (ABC)?
Customer support
Ticket topics
Number of tickets or time spent
Which help articles or fixes would cut volume most?
Personal budget
Expense categories
Money spent
Where would a cut make a real difference?
Software
Error types or slow pages
Occurrences or total delay
Which bugs affect users most?
Tips for a better Pareto chart
Measure what matters. Counting defects is easy, but ranking by cost, time lost or customer impact often changes the order. Try both.
Keep categories comparable. Mixing a broad group ("Electrical") with a narrow one ("Blown fuse") hides the real pattern.
Use the same time period for every category, and compare a before-and-after chart to check that a fix worked.
Do not over-trust 80/20. If the top 20% hold less than half of the total, the data is fairly flat and you may need finer categories or a different measure.
Keep "Other" small. If the Other bar is one of the largest, break it down into its own categories.
Frequently asked questions
What is Pareto analysis?
Pareto analysis is a way to rank categories by size to see which few contribute most of a total. You sort the categories from largest to smallest, compute each one's share and the running (cumulative) percentage, and focus on the top categories that together reach about 80% of the total.
What is the 80/20 rule?
The 80/20 rule, or Pareto principle, is the observation that in many situations roughly 80% of the effects come from about 20% of the causes, for example most defects from a few causes or most revenue from a few customers. It is a rule of thumb, not a law: real data might be 70/30 or 90/10, which is why this tool reports your actual numbers.
How is the cumulative percentage calculated?
After sorting from largest to smallest, the cumulative value of a category is its value plus the values of all categories above it. The cumulative percentage is that cumulative value divided by the grand total, times 100. The last category always reaches 100%.
What are the vital few?
The vital few are the smallest set of top categories whose cumulative percentage reaches the cutoff line (80% by default). The tool counts them, colors them dark green on the chart and marks them in the table. The remaining categories are sometimes called the useful many or trivial many.
What do the A, B and C classes mean?
They follow common ABC analysis: class A holds the categories that bring the running total up to the cutoff (80%), class B the next ones up to 95%, and class C the rest. Inventory and sales teams use the classes to decide how closely to manage each item.
Why is Other shown last?
In a standard Pareto chart a catch-all Other bar is placed at the far right even if it is larger than some single categories, because it is a mix of small causes rather than one cause to act on. You can turn this off to sort Other by its value like any other category.
Can I use negative numbers or percentages?
Use counts, amounts or costs of zero or more. Negative values are ignored because a share of a total cannot be negative. Percent signs and currency symbols are accepted and stripped, and repeated labels are added together.
Are all the tools on FreeToolCabin tested for quality and accuracy?
Yes! Every tool on our site undergoes automated Q/A testing in real browser environments to ensure high precision, correct output, and zero errors. If you happen to spot a bug or have a suggestion, please contact us at [email protected] and our team will review it right away.