Are online IQ tests accurate?

The honest answer is: an online IQ test gives a rough estimate at best, and some give no meaningful estimate at all. Whether a result is worth anything depends on a few things you can usually check yourself.

What makes any test trustworthy

Psychologists judge a test on three main questions.

Is it reliable?

A reliable test gives similar scores when the same person takes it twice, and its questions agree with one another. Reliability rises with the number of good questions. A well-built 16-item reasoning test can reach a reliability of about 0.8, which still leaves a margin of error of roughly ±13 IQ points. A full clinical battery narrows that to about ±4.

Is it valid?

A valid test measures what it claims to measure. For reasoning tests, that means puzzles with one clearly correct answer, which you solve by finding the rule rather than by guessing or spotting a quirk in the options. Poorly built puzzles can often be solved by looking at the answer choices alone. Studies of popular matrix tests have found that a large share of items have this weakness.

Who is it compared with?

An IQ score is a rank, so it depends entirely on the comparison group. Clinical tests are normed on large samples chosen to match the population. Online tests usually compare you with the people who happened to take that test, who are not a random sample. Some sites publish no comparison group at all; their numbers are effectively made up.

Red flags

Be sceptical of any online test that:

• Hides the result behind a payment or an email sign-up, especially as a cheap “trial” that turns into a subscription. Read why “free” IQ tests ask for payment.
• Gives a single exact number from a short quiz, with no margin of error.
• Sells certificates or calls itself “official” or “certified”. No online quiz has that status.
• Explains nothing: no method, no norms, no limits.
• Uses the same fixed questions for everyone, which makes leaked answers and practice effects worse.

Green flags

A more trustworthy online test will:

• tell you how many questions there are and how long you have,
• report a range and state its margin of error,
• say who your score is compared with,
• show you the answers and explain them afterwards,
• be upfront that it is an estimate, not a diagnosis.

How this site handles it

We try to tick the green boxes and avoid the red ones:

• The full result is free and instant: no email, no account, no payment.
• You get an estimated range, labelled as an entertainment estimate, and the range narrows if you answer 16 more questions.
• Every puzzle is generated by our own code, checked so that exactly one option fits the rule, and tested so that the answer cannot be spotted from the options alone.
• The methodology page publishes the formula, the version of the norms in use and its limits. Our first norms are provisional design targets that will be replaced by measured data.

So, should you trust your score?

Treat any online score as a rough indication that can easily be 10 points out, more on a short test. It can be a fun way to learn how reasoning puzzles work. It should never be used for medical, educational or employment decisions.

If you want an online result that is honest about its limits, try the free quick test.