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What is the Pareto Principle (80/20 Rule)

Also known as: Pareto principle, Pareto, 80/20 rule, 80-20 rule, law of the vital few, Pareto chart, Pareto analysis

Definition

The Pareto principle, or 80/20 rule, says a small share of causes usually produces most of the results, such as a few products bringing in most of the profit.

Why it matters

A business owner has limited time and money, and the Pareto principle shows where to spend them first.

Common mistakes

Expecting the two numbers to add up to 100. They measure different things, a share of the causes and a share of the results, so 80/10 or 90/20 are valid findings too.

Related terms

Worked exampleIllustration

A Pareto sort of a café menu

A café owner wants to know which menu items really carry the business.

  1. Collect

    Export a year of sales from the till and work out the gross profit of each menu item: its sales minus the direct cost of its ingredients.

  2. Sort

    Sort the items from the highest gross profit to the lowest.

  3. Add it up

    Add a cumulative percent column: each item's gross profit plus everything above it, as a share of the total.

  4. Draw it

    Plot the items as bars and the cumulative percent as a line. The line climbs steeply at first, then flattens.

  5. Cut

    Draw the cut where the line starts to flatten. The items above it are the vital few.

The owner protects the vital few first: they never run out, they get the best place on the menu and their prices are reviewed first. The rest of the menu is managed, not ignored.

Illustration

Where the next hour goes

Spread evenly, 3 of 8 hours reach the items that carry 70% of the profit. The average hour lands on an item worth 12.5% of it.

Share of the gross profitHours this week

  1. Coffee34%

  2. Croissants20%

  3. Sandwiches16%

  4. Cakes10%

  5. Salads7%

  6. Juice6%

  7. Tea4%

  8. Soup3%

  • The vital few, 70% of the profit
  • One hour of the owner's time

Spread evenly, 3 of 8 hours reach the items that carry 70% of the profit. The average hour lands on an item worth 12.5% of it.

The café menu from the example, each item's share of the gross profit, and an example week of 8 hours the owner spends improving the menu. The sort only pays off when the hours follow it.

Sort, add up, cut

The top 3 of 8 items, 37.5% of the menu, bring 70% of the gross profit.0%50%100%34%⁨Coffee⁩20%⁨Croissants⁩16%⁨Sandwiches⁩10%⁨Cakes⁩7%⁨Salads⁩6%⁨Juice⁩4%⁨Tea⁩3%⁨Soup⁩⁨70%⁩⁨The cut⁩⁨Running total⁩

The top 3 of 8 items, 37.5% of the menu, bring 70% of the gross profit.

Illustrative café menu, sorted by each item's share of a year's gross profit. The line adds the shares up. Move the cut to where the line starts to flatten: the items above it are the vital few.

Definition

The Pareto principle, also called the 80/20 rule, is a rule of thumb about uneven distributions: a small share of the causes, products or customers usually accounts for most of the results. It describes a pattern that shows up again and again, not a law, and the split is rarely exactly 80/20. The name goes back to the economist Vilfredo Pareto, who documented in his Cours d'économie politique (Lausanne, 1896 to 1897) that land and income were concentrated in a small share of the population, with about 80% of the land in Italy owned by about 20% of the people. Pareto himself did not state an 80/20 rule. The quality pioneer Joseph M. Juran later pointed out that the same pattern appears almost everywhere, gave it Pareto's name and coined the phrase the vital few. The practical tool is the Pareto chart, one of the seven basic quality tools: the categories drawn as bars sorted from largest to smallest, a cumulative percent line on a second axis that climbs to 100%, and a cut where the vital few end.

Why it matters

Often a few products bring in most of the profit, a few customers take most of the service time, and a few causes are behind most of the complaints. Sorting the data shows which few matter, so you can focus effort where most of the result sits. It pairs naturally with the 5 Whys: Pareto picks which problem to work on, and the 5 Whys finds out why it happens. The rule does not fit everywhere. Tax, compliance and safety tasks have to be done in full whatever their share of the result, and in a small dataset the vital few may be nothing more than noise.

Directly related: 5 Whys, Bottleneck, Gross margin.

Improvement tips

  • Sort before you decide: list the causes, products or customers, sort them from largest to smallest and add a cumulative percent column.
  • Sort customers by the gross profit they bring, not by revenue, to find the ones that really carry the business.
  • Track customer complaints for a month, group them by cause and fix the biggest group first.
  • Once you know which problem to fix first, use the 5 Whys to find out why it happens.
  • Review your task list and focus on the small number of projects that will deliver the most business value.

Common mistakes

  • Treating 80/20 as an exact law and arguing about the ratio instead of acting on the vital few.
  • Ignoring the remaining customers or products entirely, rather than managing them efficiently.
  • Applying it to tax, compliance or safety tasks, which have to be done in full whatever their share of the result.
  • Drawing conclusions from too little data, where the vital few may be nothing more than noise.

Related terms

OperationsBeginner

5 Whys

5 Whys is a way to find the root cause of a problem: you ask why it happened, then why again, usually about five times, until you reach a cause you can fix.

OperationsBeginner

Bottleneck

A bottleneck is the slowest step in a process, the one that sets how much the whole business can deliver. In a small business, it is often the owner.

FinanceBeginner

Gross margin

Gross margin is the share of revenue left after the cost of goods sold: (revenue - COGS) ÷ revenue × 100. At 60%, 60 agorot of each shekel remain.

Quick check

How can a business owner apply the Pareto principle to customer support?

Choose an answer

Frequently asked questions

How do I apply the Pareto principle to my business before I launch?
Before launch there is little data to sort, so use the idea as a filter rather than a calculation. Put your best hours into the few tasks that lead directly to your first sales, such as the offer and talking to customers, and leave minor details like logos for later. Once real sales data exists, sort it properly.
How can the 80-20 rule help me define my initial target market?
Before you sell, you cannot know which customer segment will bring most of your sales, but you can find out quickly. Test a few segments, then sort the first months of sales by segment and put your marketing where the results cluster. This keeps you from spreading a small budget across audiences that do not buy.
How do I plan my product features using the Pareto principle?
List the problems your customers most need solved and build the few features that cover most of them first. This lets you launch a working product quickly and cheaply, without spending months on complex extras. Real customer feedback then shows what to add next.
Does the 80-20 rule mean I can ignore the rest of my business tasks?
The rule does not mean you can ignore essential tasks like taxes, legal setup or safety, which must always be done in full whatever their share of the result. It helps you decide where to spend your best working hours for the biggest impact. Put your best energy into growth tasks and handle routine tasks efficiently.
Why am I working eighty hours a week but my business revenue is flat?
This problem happens when you spend most of your time on low-value admin tasks that do not drive business growth. If your schedule is filled with minor customer requests or paperwork, you cannot focus on sales and strategy. You must identify and delegate the routine tasks that consume your time without adding profit.
How do I identify the customers who generate the most profit?
Run a sales report for the past year, sort your customers by the gross profit they generated, not just their revenue, and add a cumulative percent column. You will usually find a small group of customers who bring in most of your profit. Focus on serving these customers well and look for more customers like them.
How do I apply the Pareto principle to reduce customer support tickets?
Track your customer complaints for a month, group them by cause and sort the groups from largest to smallest. Usually a few causes account for most of the tickets. Fix the biggest group first, then use the 5 Whys to find out why that cause keeps happening.
Is it a mistake to assume the split is always exactly 80/20?
Yes. 80/20 is shorthand, and the real split in your data might be 90/20, 70/30 or 80/10. The two numbers measure different things, a share of the causes and a share of the results, so they do not have to add up to 100. What matters is that a small number of causes usually produces most of the results, so act on that small group.
What is the Pareto principle in simple words?
The Pareto principle, also known as the 80/20 rule, says that a small part of what you do usually brings most of your results. For example, a few of your products may bring in most of your sales. It is a rule of thumb that helps you decide what to work on first, not an exact law.
Is the Pareto principle a strict mathematical law that I must calculate?
This principle is not a strict law or complex math formula, but rather a common pattern observed in business and life. You do not need advanced statistics to use it, as you just need to look at your data to see where your best results come from. It is a simple tool to help you prioritize your day.
Do I need an analyst to apply the 80-20 rule to my company?
You do not need to hire an analyst or buy special software to apply this rule to your operations. You can do it yourself in a simple spreadsheet: sort a column from largest to smallest and add a running total. Tracking where your profit comes from will clarify where to focus your time.
What is the risk of treating all business tasks and customers as equally important?
The risk of treating everything as equal is that you will spread your time and budget too thin, leading to slow growth and exhaustion. You will waste valuable hours on low-profit clients who demand constant attention, while neglecting your best customers. Prioritizing your tasks is essential to scale your business.

Sources: Vilfredo Pareto, Cours d'économie politique, Lausanne, 1896 to 1897, Joseph M. Juran, Quality Control Handbook, 1951, Juran Institute, A Guide to the Pareto Principle (80/20 Rule) and Pareto Analysis, ASQ (American Society for Quality), Pareto Chart

Last reviewed: 2026-09-23

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