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Mozart’s figure is one of the few on this site with a real academic origin — a 1926 Stanford study that estimated IQs for three hundred dead people, and whose method is more interesting than its results.
Cox’s method reads surviving biography and converts documented childhood achievements into a score. It measures how much of a childhood was written down at least as much as it measures the child.
Set the claim aside for a moment. If someone genuinely scored in this range, here is what that would represent.
Average is 100 by construction, and about two-thirds of people fall between 85 and 115. Take the test to place your own score on this scale.
| Score range | Classification | Share of people | What it indicates |
|---|---|---|---|
| 85 – 114 | Average | ~68% | The range most people fall into. |
| 115 – 129 | Above average | ~13.6% | Roughly one person in seven. |
| 130 – 144 | Gifted | ~2% | The threshold most high-IQ societies use. |
| Above 144 | Highly gifted | ~0.1% | Figures above this range are extrapolated from the curve rather than measured. |
Percentages are approximate and describe a normal distribution. The same number means different things on tests with different standard deviations.
Thirty questions gives you a measured position on this exact scale — your score, your percentile and the ability breakdown behind it.
Find out in 30 minutes →Mozart was born in Salzburg in 1756. His father Leopold was deputy Kapellmeister to the archbishop and a published author on violin technique, and from 1762 he took Wolfgang and his sister Nannerl on performing tours through Munich, Vienna, Paris, London and Rome.
The London stay produced the first symphony, written when he was eight. The Rome visit produced the story that has done more for his reputation than any other: that having heard Allegri’s Miserere once in the Sistine Chapel, he wrote it out from memory.
He moved to Vienna in 1781 and worked freelance — Le nozze di Figaro, Don Giovanni, Così fan tutte, Die Zauberflöte — until his death in 1791 at thirty-five, with the Requiem unfinished.
The estimate above rests on this record. Every entry here is a matter of public fact, which is more than can be said for the number itself.
Following a claim back to its first appearance is the part almost nobody does — and it is what most people are actually asking.
This entry, Voltaire and Goethe all come from the same 1926 volume, and reading them together shows the method’s weakness clearly. Cox’s scores correlate with how much biographical material survived about a subject’s childhood — and the families who documented their children most thoroughly were the wealthy, the literate and the already-famous.
Mozart is the extreme case. His father Leopold was a professional musician who kept detailed records, wrote letters constantly, and toured his children through the courts of Europe as a business. Almost no other eighteenth-century childhood is documented in comparable detail. A method that rewards documentation will rank him highly whatever his ability was.
That is not an argument that Mozart was ordinary. It is an argument that the number is measuring Leopold’s bookkeeping alongside Wolfgang’s mind, and that the two cannot be separated after the fact.
How we read a number →The origin of the figure. Cox gives two estimates per subject, one for childhood and one for youth, and states plainly that both are inferences from biography.
The standard chronological catalogue. Establishes the dating of the early works the estimate rests on.
Contemporary letters documenting the childhood tours, including the 1770 Rome visit. Also the reason so much detail survives at all.
Intelligence testing did not exist until more than a century after Mozart’s death.
Source URLs and first-appearance date pending audit.
Higher than either Cox estimate and not attributable to her study.
The figures that circulate for Wolfgang Amadeus Mozart, what we were able to confirm, and where the two diverge.
Figures from 150 to 165 circulate, and unusually for this site most of them do trace back to something real: Catharine Cox’s 1926 estimates.
Cox never claimed to have tested anybody. Her study assigned estimated IQs to historical figures by scoring the recorded achievements of their childhoods against the developmental norms of the day. The number is a scholarly inference from documents. It becomes false only when it is repeated as though somebody sat Mozart down with a test.
The lower figures are Cox’s own two estimates. The 165 appears later, in popular sources, and is not hers.
Want a number that does hold up? Every figure on this page is somebody’s claim. Take the 30-question test and get a percentile you can check rather than a figure you have to trust.
He was never tested — intelligence testing did not exist in the eighteenth century. The 150–165 figures come from Catharine Cox’s 1926 historiometric study, which estimated scores from biographical records.
It is honest scholarship, but it measures documentation as much as ability. Subjects whose childhoods were recorded in detail score higher, and Mozart’s was recorded more thoroughly than almost anyone’s.
It is reported in contemporary correspondence following the family’s April 1770 visit to Rome. It is the best-attested of the prodigy stories, though the piece is more repetitive than its reputation suggests, which makes the feat more plausible rather than less.
Eight. It was written in London in 1764 during the family’s European tour.
Goethe, at an estimated 210 — the highest of the three hundred subjects. Mozart, Voltaire and Goethe are all profiled on this site from the same source.
Early achievement and adult ability are related but far from the same thing. Most child prodigies do not become historically significant adults, and most historically significant adults were not prodigies.
You can find out in about fifteen minutes. The IQ Metrics assessment is 30 questions, scored on the same 100-mean scale used throughout this page, so your result and the estimate above are at least expressed in the same units — one measured, one inferred. Once you have a number, the leaderboard shows where it would sit, and how we score and norm it explains the benchmarking.
From the documented record rather than a test — the method is named above and set out in full under how we read a number. Compare it against the other musicians profiles, starting with Brian May.
Portrait © Matthew Yohe, CC BY-SA 3.0. The background-removed portrait above is a derivative work and is likewise offered under the same licence. · Portrait © Debbie Rowe / The Royal Society, CC BY-SA 3.0. The background-removed portrait above is a derivative work and is likewise offered under the same licence. · Portrait by Christopher Smith, U.S. Department of Health and Human Services — a work of the U.S. federal government, public domain. Background removed for the portrait above.
Thirty questions, scored against general-population benchmarks. Your score, your percentile, your ability breakdown and a printable IIF certificate.
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