HOW WE STARTED

Built in 14 days because the existing IQ tests were terrible.

— Don't just read about it
Find out YOUR exact IQ
20-min calibrated test · real psychometrics
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Core Brain wasn't supposed to be a business. It started as a weekend frustration with how broken online IQ testing had become.

— Try one before you read on
Which number completes the sequence: 2, 6, 12, 20, 30, ?

The problem

→Pause. Find out YOUR IQ before you keep reading.

I'd been curious about my own IQ — properly, not "8th-grade-teacher-said-I-was-smart" curious. I started looking around at what was available online. The landscape was bleak:

The clickbait tier. Fifty test sites that ask you 5 to 10 multiple-choice questions and then dump a "Your IQ is 137!" screen designed to make you share it on Facebook. No methodology disclosure. No confidence interval. No way to verify the number means anything.

The lead-magnet tier. Sites that let you take a 20-question test, then lock the result behind a $49 or $99 paywall after capturing your email. Designed to push you into a refund-process you'll never use.

The legit-but-painful tier. Real psychometric communities (r/cognitiveTesting, cognitivemetrics.com, RIOT IQ) running real tests with real calibration — but the UX requires a Reddit account, a willingness to dig through whitepapers, and tolerance for tests that take 45+ minutes.

There was no middle ground. So I built one.

"An IQ test should give you a real number with an honest confidence interval — and it should take twenty minutes, not three hours."

The build

→Curious how YOU score? 20-min calibrated test.

I gave myself two weeks. The constraint was: ship something genuinely calibrated, not a quiz dressed up as a test. The core technical requirement was real Item Response Theory scoring — 3PL Bayesian MAP estimation, the same statistical framework as the WAIS-IV.

Days 1-3
Built the IRT 3PL scoring engine from scratch in TypeScript. Newton-Raphson MAP estimator, Fisher information for SEM, 95% confidence interval computation.
Days 4-7
Calibrated the item bank — 200 items across 5 difficulty tiers, each with discrimination/difficulty/guessing parameters derived deterministically from item content.
Days 8-10
Built the UI. Six cognitive axes, stratified sampling, per-axis sub-theta estimation. Six-axis radar chart, bell curve overlay, downloadable PDF certificate.
Days 11-12
Stripe payment integration. Single $15 unlock, no subscriptions. Server-side verification of every paymentIntent.
Days 13-14
SEO foundation. Domain on Vercel. 94 programmatic landing pages built from MBTI types, career averages, IQ score explanations, age cohorts.
Day 14
Live at corebrain.app.

What's next

→The numbers above? Find out where YOU land.

The IQ test itself is feature-complete. The next chapter is the Brain Training dashboard — a growing suite of calibrated cognitive exercises (reaction time, working memory, attention, fluid reasoning, spatial rotation) with a real progress dashboard. Access is private while invites are being opened.

If you want to follow along: the calibrated test is at the bottom of every page. Take it. Tell me what you think.

Take the test →
Want YOUR exact IQ? Take the calibrated 20-min test.
Start →