Stanine Score Calculator

Work out stanine score instantly with clear inputs, formula shown and shareable results.

About Stanine Score Calculator

Stanines divide the normal distribution into nine bands with mean 5 and standard deviation 2, so stanine = 5 + 2z rounded. The 75th percentile is z = 0.674, giving an exact stanine of 6.35 which rounds to 6 - the band covering the next 12% above the middle 20%. The coarseness is deliberate, discouraging over-interpretation of small differences.

Formulas

Stanine

stanine = round(5 + 2z), bounded to 1-9

Band widths

4, 7, 12, 17, 20, 17, 12, 7 and 4 percent of the population

Worked example

With the default values below, Stanine Score Calculator returns Stanine of 6. Change any input above and every figure here is recalculated in your browser.

Inputs used

Percentile rankaccepts 0.01–99.99 %: 75 %
Raw score for reference: 42

Results

Stanine: 6 /9
Unrounded Stanine: 6.349
Underlying z Score: 0.6745
Population Band: next 17%

Step by step

1Values used
2Stanine
3Band widths
4Stanine= 6 /9
5Unrounded Stanine= 6.349
6Underlying z Score= 0.6745
7Population Band= next 17%

Assumptions and limits

The result is derived only from the 2 inputs listed above. Anything not among them is not part of the calculation.
In particular, this calculator does not take inflation, tax, fees or charges or compounding frequency into account.
Figures are rounded for display to 4 decimal places, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.

How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.

Frequently Asked Questions

Why only nine bands?

The scale was designed for punched cards in the 1940s, needing a single digit. The coarseness usefully discourages reading meaning into trivial score gaps.

Are stanine bands equal width?

In z units yes, at half a standard deviation each, but in population terms they vary from 4% at the extremes to 20% in the middle.