Convert a supplied score using a transparent normal model. Every result states its scale and keeps the distinction between theoretical conversion and an official test percentile visible.
points
Percentile84.1thNormal-model estimate
Directional rarityabout 1 in 6.3at or above
Standard position+1.00σ1.00 SD above the mean
This is a theoretical normal-distribution conversion, not a test result, diagnosis, confidence interval, or eligibility decision. Official percentiles depend on the exact test, edition, age norms, and score report.
How the conversion works
The calculator subtracts the selected mean from the score, divides by the selected standard deviation, and applies the standard normal cumulative distribution. Upper-tail rarity uses a numerically stable survival calculation rather than subtracting a rounded percentile from 100.
See the complete formulas, implementation limits, and fixed verification values in the methodology.