IQ Score Converter
Convert any IQ or standardized test score between Wechsler, Stanford-Binet, Cattell, SAT, ACT, and GRE scales. All conversions use z-score transformation and run entirely in your browser.
Convert Your Score
All conversions use z-score transformation. Test score equivalents (SAT, ACT, GRE) are approximate.
Scale Reference Guide
Wechsler (WAIS/WISC)
The most widely used IQ scale worldwide. Used by the WAIS-IV and WISC-V. Mean = 100, SD = 15.
Range: 40–160 | Mean: 100 | SD: 15
Stanford-Binet 5
Modern Stanford-Binet (5th edition) uses the same scale as Wechsler. Earlier editions used SD = 16. Mean = 100, SD = 15.
Range: 40–160 | Mean: 100 | SD: 15
Cattell (Culture Fair)
Cattell's Culture Fair Intelligence Test uses a wider standard deviation. Mean = 100, SD = 24. Scores appear more extreme than Wechsler.
Range: 4–196 | Mean: 100 | SD: 24
Mensa Qualifying Score
Mensa accepts the top 2% on any recognized IQ test. The qualifying threshold is approximately 130 on the Wechsler scale or 132 on the Cattell scale.
Range: 40–160 | Mean: 100 | SD: 15
SAT (pre-2016 recentered)
ApproximateApproximate IQ equivalents for SAT scores. Based on recentered SAT (pre-2016 format, 400–1600 combined). Correlation with IQ is roughly 0.80–0.85.
Range: 400–1600 | Mean: 1000 | SD: 200
ACT Composite
ApproximateApproximate IQ equivalents for ACT composite scores. Based on published ACT norms. Correlation with IQ is roughly 0.75–0.80.
Range: 1–36 | Mean: 20.8 | SD: 5.8
GRE (Verbal + Quant)
ApproximateApproximate IQ equivalents for combined GRE Verbal + Quantitative scores. GRE takers are a self-selected, above-average group, so conversions are rough estimates.
Range: 260–340 | Mean: 302 | SD: 14.5
Now interpret the converted score
Use the converted value to see its percentile, distance from the mean, and practical meaning.
How IQ Scale Conversion Works
Different IQ tests report scores on different scales. The Wechsler tests (WAIS-IV, WISC-V) and the modern Stanford-Binet 5 both use a mean of 100 and standard deviation of 15, but the Cattell Culture Fair test uses a standard deviation of 24. This makes direct comparison misleading without conversion.
The converter uses z-score transformation: it first calculates how many standard deviations your score is from the mean on the source scale, then maps that position onto each target scale. For IQ-to-IQ conversions this is mathematically precise. For standardized test equivalents (SAT, ACT, GRE), the conversions are approximate estimates based on published correlation data.
Understanding the Wechsler vs. Cattell Difference
The most common source of confusion in IQ scores is the difference between the Wechsler scale (SD = 15) and the Cattell scale (SD = 24). A Cattell score of 148 sounds dramatically high, but it is equivalent to a Wechsler score of 130; both represent the 98th percentile. Online IQ tests sometimes report on the Cattell scale without making this clear, which can lead to inflated expectations.
For a deeper comparison of IQ testing systems, see our guide to WAIS vs. Stanford-Binet vs. online IQ tests.
SAT, ACT, and GRE as IQ Proxies
Standardized academic tests correlate with IQ but are not interchangeable with it. Research shows correlations of approximately 0.80–0.85 for the SAT, 0.75–0.80 for the ACT, and somewhat lower for the GRE (which draws from a pre-selected, above-average population). These conversions should be treated as rough estimates, not precise equivalencies.
For more on this topic, see our article on LSAT, MCAT, and GRE IQ correlations.
Important Caveats About Score Conversion
Once you have converted your score, explore what it means with our IQ Score Meaning tool, or see where it falls on the bell curve with the IQ Standard Deviation Calculator. You can also check your exact percentile ranking.
- IQ-to-IQ conversions (Wechsler, Stanford-Binet, Cattell) are mathematically precise when both tests measure the same construct.
- Test score equivalents (SAT, ACT, GRE) are statistical approximations. The SAT measures learned academic skills in addition to general cognitive ability.
- Score capping: when a conversion falls outside a scale's valid range, it is capped to the nearest boundary. Capped scores are marked with an asterisk (*).
- Mensa eligibility requires the top 2% on a proctored, recognized IQ test, not an online converter. This tool shows whether your score falls in the qualifying range.
To read a converted score off a chart rather than a calculator, see our full IQ percentile table, which lists the percentile, classification and rarity for every score from 70 to 160.
Frequently Asked Questions
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