Can be converted from EQ to IQ

Please also note our technically updated new editions of:

Thinking games with Elfe and Mathis - promoting logical thinking skills for preschool and elementary school children
conText - promoting reading comprehension by working with texts.

Standard value calculator *

New! Now also as a mobile version (beta)

The following small calculator will help you convert IQ scores, T scores, standard scores, value points (Wechsler intelligence tests), the PISA scale and percentile ranks. Please move the slider or enter a value in a field and press the return key:

* The standard value calculator uses the Chart.js library to display the diagram.

** The calculation of the confidence interval is based on the standard estimation error (cf. Amelang & Schmidt-Atzert, 2006, p. 51) and taking into account the regression towards the center. Only values ​​between 0 and 1 are permitted for reliability. The confidence interval is output depending on the selected standard value scale. If "cumulative" is selected, the confidence interval is output as a percentile band.


Norm values ​​serve to relate the results of a single person to the values ​​of a comparison group. To convert an individual value into a normal value, it is generally assumed that the values ​​in the comparison group are distributed in the form of a bell, i.e. that many people have average values ​​and few people have extreme values. Such so-called normal distributions are characterized by a mean value M and a standard deviation SD. The latter represents a measure of the variability of the values ​​within the comparison group, i.e. the breadth of the distribution. A norm value indicates how many standard deviations the value of an individual person is from the group mean. There are different scales in which the standard values ​​can be expressed and which can be converted directly into one another.

Probably the best-known norm value scale is the IQ scale with a mean value of 100 and a standard deviation of 15. A value of 100 means a completely normal result, from 115 one usually speaks of an above-average result, from 85 of a below-average result. Analogously, these results can also be converted into z-values, T-values, standard values ​​(SW values), value points (e.g. Wechsler scales) or the Pisa scale.

AverageStandard deviation
T value5010
IQ score10015
SW value10010
Value point103
Pisa scale500100

The situation is different with percentile ranks: They indicate how many people in the comparison group did equally well or worse. A percentile rank of 50 means that 50% did equally well or worse, while the other 50% did better. So the person is exactly on average. Higher values ​​represent an above-average result, lower values ​​a below-average result.

The standard value calculator is intended to facilitate the conversion of these different scales. You can either set values ​​with the mouse using the slider or enter them directly into the text fields. The program automatically calculates the correspondence in the other standard value scales.

Terms of Use

You can use the standard value calculator for private purposes as well as in the context of your profession (e.g. as a psychologist, doctor, special needs teacher, lecturer, etc.) freely and free of charge. However, selling or changing the program is not permitted. No liability is accepted for any malfunctions. If you like the program or if you find it useful, we would be delighted if you would post a link to this page on your own homepage, in a blog or in a forum.


Amelang, M. & Schmidt-Atzert, L. (2006). Psychological diagnosis and intervention. Heidelberg: Springer.

Quotable source: Lenhard, W. & Lenhard, A. (2015). Standard value calculator. available at: Bibergau: Psychometrica. DOI: 10.13140 / RG.2.1.4592.5363