IQ Percentile Calculator

A free, real-time IQ-to-percentile calculator for psychology blogs, education sites, quiz pages, and IQ-comparison articles. One line of HTML, no signup, no attribution required.

<iframe
  src="https://corebrain.app/embed/iq-percentile/"
  width="100%"
  height="400"
  style="border:0;border-radius:16px;max-width:420px"
  loading="lazy"
  title="IQ Percentile Calculator">
</iframe>

Why embed it

How the math works

The calculator uses the standard Wechsler IQ distribution — mean 100, standard deviation 15. The percentile is computed from the cumulative normal distribution function using the Abramowitz & Stegun erf approximation. Classifications follow conventional psychometric bands:

• ≥ 160 — Profoundly gifted (less than 1 in 30,000)
• 145–159 — Highly gifted (top 0.13%)
• 130–144 — Gifted (top 2.3%, Mensa cutoff)
• 120–129 — Superior intelligence (top 9%)
• 110–119 — High average
• 90–109 — Average (68% of people)
• 80–89 — Low average
• 70–79 — Borderline
• < 70 — Extremely low (bottom 2%)

FAQ

Is the widget really free?

Yes. No signup, no API key, no rate limit. Embed it on as many pages as you want.

Do I need to credit Core Brain?

The widget includes a small "Powered by Core Brain" footer. You don't need to add anything else — the attribution is built in.

Will the widget break my page's loading speed?

No. The iframe uses loading="lazy" so it only loads when scrolled into view. The widget itself is <5KB of HTML/CSS/JS.

Can I customize the colors?

Not yet. The widget uses Core Brain's dark theme to match psychometric and education aesthetics. Light-theme support is planned.

Is the underlying IQ data accurate?

Yes — the percentile calculation is mathematically exact for the Wechsler distribution. The classification bands match standard psychometric convention. For your own actual IQ score, take the full 20-minute test at corebrain.app (IRT 3PL Bayesian scoring, same framework as WAIS).

Want your real IQ?

The widget tells you what an IQ score means. To get your actual IQ, take the full Core Brain test — 20 minutes, real psychometric scoring, six cognitive axes, 95% confidence interval.

https://corebrain.app/embed/iq-percentile/#137

<iframe src="https://corebrain.app/embed/iq-percentile/"
  width="320" height="380" style="border:0;border-radius:14px">
</iframe>

POST /api/v1/score
Authorization: Bearer YOUR_KEY
{ "items": [
    { "a": 1.4, "b": 0.6, "c": 0.25, "u": 1 },
    { "a": 1.1, "b": -0.4, "c": 0.25, "u": 0 }
] }
// → { theta, iq, ci95: [low, high], reliability }