How often should I take an IQ test?

There is no standard recommendation for how often a person 'should' take an IQ test. For self-knowledge purposes, once is enough — a single result with documented standard error of measurement provides as much information as you can use. Repeated testing on the same instrument produces inflated scores due to practice effects. For research or clinical follow-up purposes, IQ is typically retested at intervals of 1 to 5 years, with longer intervals preferred to minimize practice effects. After a neurological event (stroke, traumatic brain injury), follow-up testing at 3 months, 6 months, and 12 months is common to track recovery.

This question comes up frequently from users of free online IQ tests and from people considering whether to pursue a clinical evaluation. The full answer depends on context — what the score will be used for, how recently the test was administered, and what other information is available. The brief answer above captures the broad consensus from the published research literature; the linked deep-dive articles cover the underlying evidence in more detail.

Related considerations include the standard error of measurement on the relevant test, the population the test was normed against, and the specific cognitive abilities the test samples. A score is much more informative when interpreted alongside these contextual variables than when reported as a bare number.

If this answer raises further questions, see the related FAQ entries listed in the sidebar and the longer-form articles on the same topic in the article library. The site is designed to provide layered depth: the FAQ entries offer concise answers, the deep-dive articles offer the underlying research, and the score-interpretation pages tie the abstract concepts to specific result bands.