About the 1916 Stanford-Binet
Lewis Terman's 1916 Stanford Revision of the Binet-Simon scale is the most important single document in the history of IQ testing. It is the book that:
- Coined the term IQ as a number. Before Terman, IQ was a ratio expressed as a decimal (mental age / chronological age). Terman multiplied by 100 to produce an integer, which became the convention every IQ test has used since.
- Established the 100-point average. Terman set the mean IQ of his Californian standardization sample to 100, defining the convention every modern test still uses.
- Made cognitive testing into a profession. The 1916 manual was the first comprehensive guide to administering and scoring an individual IQ test. It made the field operationally reproducible.
The test is age-graded: items are grouped by the age at which the average child can pass them. A child takes items at increasing age levels until they consistently fail; their mental age is calculated from how many items they passed at each level. The 1916 scale runs from Year III (age 3) through Year XIV, with an Average Adult and Superior Adult level above that.
Age levels included
Items are presented in order of difficulty, grouped by Terman's age-level system. Each item passed earns a fractional credit (in months) toward your mental age, per the original 1916 scoring rules.
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Each item has a brief instruction and a way to answer. There is no overall time limit, but the original test typically took 30-60 minutes. You can pause anytime.
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How Terman's mental age + IQ formula works
The 1916 Stanford-Binet computes mental age by adding up credits earned at each age level. The original 1916 rules:
- Start at the level below the subject's chronological age.
- Move down until you find a level where the subject passes ALL items - that is the basal age, which earns full credit.
- From the basal age upward, give partial credit for each individual item passed. The credit-per-item is fixed per level (e.g. 2 months per item at Year III, 3 months at Year XII, 4 months at Year XIV).
- Move up until you find a level where the subject fails ALL items - that is the ceiling age, beyond which no credit accumulates.
- Mental age (in months) = basal age in months + sum of all per-item credits.
Then IQ = (mental age / chronological age) × 100. So an 8-year-old (96 months) with a mental age of 108 months has an IQ of (108/96) × 100 = 112.
This is the ratio IQ formula. Modern tests (since Wechsler 1939) abandoned it for the deviation IQ: instead of comparing mental age to chronological age, modern tests compare your score to the distribution of scores in your age group, with the mean fixed at 100 and standard deviation at 15.
Source and verification
All items, instructions, and scoring criteria on this page are transcribed from:
Terman, L. M. (1916). The Measurement of Intelligence: An Explanation of and a Complete Guide for the Use of the Stanford Revision and Extension of the Binet-Simon Intelligence Scale. Boston: Houghton Mifflin Company. 362 pp.
This work is in the public domain in the United States (published before 1929). The full book is available on Internet Archive: archive.org/details/measurementofint1916term.
Items requiring physical materials, motor tasks, examiner judgment, or audio playback were excluded from this interactive version. A full list of skipped items is shown in the test interface.
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The 1916 Stanford-Binet is a historical artifact. For a contemporary IQ score using modern norms and the deviation-IQ scale, take our modern full IQ test.
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