Why tools show the 75th percentile, not the average

Why tools show the 75th percentile, not the average

When you read a Core Web Vitals score, it's the 75th percentile (the value 75% of visits stay under), not the average. Averages hide pain: a few super-fast loads can mask many slow ones.

Think of it like grading a class by the student near the bottom of the top three-quarters, not the smartest kid.

When this matters:
— Comparing your RUM tool to CrUX: make sure both show the 75th percentile, or they'll disagree for no reason.
— Setting goals: aim for the 75th percentile to pass, since that's what Google judges.

Try this: in your speed tool, find the percentile setting and switch it to 75th. Now your numbers match Google's. Suddenly the confusing gap between tools disappears. This small toggle saves real headaches.