Free GPTZero Checker
Test your writing against the perplexity and burstiness patterns GPTZero looks for — before you submit. Free, instant, and private: the check runs entirely in your browser.
What GPTZero actually measures
GPTZero relies on two signals. Perplexity measures how surprising your word choices are: language models pick the most statistically likely next word, which makes their output smooth but predictable. Burstiness measures variation — humans mix long, clause-heavy sentences with short, punchy ones, while AI tends toward uniform length. This checker estimates both, along with 40+ related patterns, and lists exactly what triggered so you can fix it.
Lower your score the right way
When you score high, the fix is to add genuine variation rather than swap synonyms. Our free humanizer does this automatically, and our guide on bypassing AI detection covers the manual techniques.
Frequently asked questions
Is this an official GPTZero tool?
No — it's an independent, free checker that measures the same kinds of signals GPTZero uses (perplexity and burstiness). Use it to estimate risk and find what to fix before you run the real thing.
How does GPTZero detect AI text?
GPTZero scores two main signals: perplexity (how predictable your word choices are) and burstiness (how much sentence length and complexity vary). AI text tends to be low-perplexity and low-burstiness — smooth and uniform. This checker flags those same patterns.
Is it free and private?
Yes. There's no signup and the analysis runs locally in your browser, so your text is never uploaded or stored.
My text scored high — what now?
Use our free humanizer to rewrite the flagged passages so they read more naturally, then re-check. The goal is to raise perplexity and burstiness back into the human range.
Beat GPTZero with one click
Humanize flagged text for free so it reads naturally and scores in the human range — no credit card required.
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