How accurate is an online IQ test
An online test can be a reasonable estimate or complete noise, and the difference is visible from the outside if you know what to look for.
What separates a usable test from a bad one
A named norm group, a stated standard deviation, a visible derivation, a fixed item set, and no payment gate in front of the score. Missing any of those, treat the number as entertainment.
Sources of error you control
Interruptions, a small screen, fatigue, and testing late at night. Sit it once, alone, on a decent screen, with the clock running uninterrupted.
What no online test can do
It cannot observe you, cannot confirm your identity, and cannot support any clinical or diagnostic claim. Those require a supervised, individually administered instrument.
Scored against age, education and area norms. Free certificate with a QR code anyone can verify.
Questions people ask
How close is it to a supervised test?
A well-built one lands in the right region. Expect a band of several points either side, not a precise figure.
Why do some sites give everyone a high score?
Stale norms and flattering conversions sell certificates. A generous number is a warning sign.