Quantiles and Percentiles
A practical guide to converting between probability levels and data thresholds.
Try This In The Plotter
Jump directly into the percentile threshold workflow and apply this guide on a live distribution chart.
Open Interactive Percentile ThresholdQuantiles As Inverse CDF
The p-quantile xp solves F(x_p) = p.
Quantiles answer threshold questions like what value marks the top 10%.
Percentiles In Practice
The 90th percentile means 90% of observations are expected at or below that value.
Percentiles are common in exam scores, quality limits, and risk thresholds.
Common Interpretation Mistakes
Do not confuse percentile rank with percent increase.
A percentile does not imply fixed spacing between values across the scale.
Related Distributions
Related Calculators