Paste the text above (or upload a file / drop in a URL) and press Scan — you get a 0–100 AI score, the lines that read machine-written marked in place, and the reasons in plain English. Checking for AI is free, instant, and anonymous scans are never stored.

20,000 characters (about 3,500 words) anonymously, and 50,000 characters (about 8,500 words) with a free account — that's a full paper or long article in one scan, where many AI checkers cap you around 5,000 characters. Bigger limits come with paid tiers.

The 0–100 number says how strongly the text shows the measurable signs of machine writing — even sentence rhythm, stock phrasing, predictable word choice. Low means it reads human, high means it reads like unedited AI. It's a signal with evidence attached, never proof of who wrote it. How to read the score →

Yes. The AI detector, the sentence heat-map, and the Cleanup tool are free, and anonymous scans are never stored.

Yes — it's tuned against current models including ChatGPT, Claude and Gemini. Deep scan runs considerably more checking, for the most accurate read.

It's built for the models people actually paste from — ChatGPT (GPT-4 and GPT-5), Claude, Gemini, Microsoft Copilot, Llama, DeepSeek, Grok, Mistral and Qwen — plus paraphrased and lightly-edited AI. It reads the statistical habits shared across large language models rather than one vendor's fingerprint, so newer models are usually caught too. No detector is perfect, which is why we always show the signals behind the score.

No detector — ours or anyone's — is 100% accurate. ScanForAI returns a signal, not a verdict: a score plus the patterns behind it, so you judge the evidence.

Formal and non-native human writing scores higher on every detector. We test against non-native writing specifically and show the reasoning, so a high score starts a conversation, not an accusation.

Anonymous scans are never stored. Signed-in scans are saved only for your history and can be deleted anytime.

It reads the statistical fingerprints of machine writing: even sentence rhythm, stock phrasing, formal register, and how predictable each next word is. ScanForAI weighs dozens of these patterns and, on deep scan, checks far more of them and far more carefully — then shows you which ones fired, not just a number.

Often, yes — schools run detectors, and unedited ChatGPT text carries measurable habits. But detectors are wrong both ways, so a flag is not proof. Check your own work first: paste it here, see what reads machine-written, and if you're wrongly flagged you'll have the evidence to discuss it.

Stay calm and bring evidence, not just denial: your draft history, notes, and a ScanForAI report showing the per-line breakdown. Ask which detector was used and its known false-positive rate. No single score is proof — most institutions know that, and the per-signal breakdown turns an accusation into a conversation.

Light grammar fixes usually don't move the score much — they clean surface errors without changing your rhythm or word choice. Heavy AI rewriting does. Our score reflects how machine-written the text reads, so lightly-corrected human writing stays low.

Yes — that's the common real case. ScanForAI scores each part on its own and marks the AI-leaning passages in place, so you see exactly which sections read machine-written instead of one blurred average for the whole document.

Honestly: good, and getting better — but no detector is a lie detector. Formal and non-native human writing can score high anywhere, and lightly-edited AI can score low. That's why we show the evidence behind every score and frame it as a signal, not a verdict. Treat it as one input, never as proof about a person.