laws & principles
Pareto principle
What is the Pareto principle?
The Pareto principle suggests that roughly 80% of effects come from about 20% of causes - the 'vital few'. In UX, this often means a small set of features, flows, or fixes delivers most of the value. The exact split varies and it’s not a precise law; treat it as a prompt to find and prioritise the high-impact minority, not a formula. You can see this in action on this page.
Also known as: 80/20 rule, Pareto's law
Prefer to watch?
Watch the recap 0:37
The demo
Ten features, sized by how much they're used. Click them to add up their share of all usage - and see how few you need to reach most of it. Try the biggest ones first.
Selected: 0% of all usage, from 0 of 10 features
Click features to total up their usage share.
What this demo shows (text version)
A bar chart of ten features whose usage is steeply uneven: the first two features account for about 80% of all use, and the remaining eight share the last 20% between them. Clicking a feature adds its share to a running total shown above the chart.
Selecting just the top two features reaches roughly 80% of all usage - a fifth of the features delivering four-fifths of the value. That is the Pareto principle, and the takeaway is to concentrate effort on the vital few that people use constantly, while remembering the long tail still matters to the people who depend on it.
Focus on the vital few - the 20% that delivers 80% of value - because improving the rest rarely gives proportional returns. You can see this in action on this page.
You reached four-fifths of all usage by selecting just a couple of features out of ten. That lopsidedness is the Pareto principle, and it changes where you spend effort: the vital few deserve most of your craft, while the trivial many can wait - or go.
The number isn't magic - it's not always exactly 80/20, and you shouldn't force it. The useful move is to actually look at your usage data and find the real distribution, which is almost always lopsided. Polish the few things people do constantly before you perfect the ones they touch once a year.
Two cautions. The long tail still matters to someone - a rarely-used feature can be mission-critical for the person who needs it, so "20% of use" is not the same as "safe to delete". And don't let the vital few become an excuse to neglect accessibility or edge cases that decide whether people can use the product at all.
Try the Pareto principle UX in action on this page - you’ll see how focusing on the vital few drives disproportionate value. The Pareto principle UX isn’t about rigid math; it’s about spotting what matters most and building around it - you can test that here.
Use the Pareto principle UX to identify the vital few features that deliver most impact - you can test this concept interactively on this page. The Pareto principle UX isn’t about rigid percentages - it’s a prompt to prioritise what matters most, and you can experiment with that here.