AI Content Detector
Check whether text was written by AI or a human. Get an AI probability score, sentence-level signals, and a confidence rating — so you can review and improve content before publishing.
What Is an AI Content Detector?
An AI content detector is a tool that analyzes text and estimates the probability that it was written by artificial intelligence rather than a human. It looks for writing patterns associated with AI language models — such as uniform sentence length, low variation in sentence structure, repetitive phrasing, and predictable word choices — and returns a likelihood score.
AI detectors do not read meaning the way a human editor would. They analyze statistical and structural patterns in the text and compare those patterns against what AI-generated writing typically looks like. The result is a probability estimate, not a certainty.
AI Probability Score
Returns a 0–100% score showing how likely the text is to have been written by AI, with a confidence rating of low, medium, or high.
Signal Breakdown
Shows individual writing signals — repetitive phrasing, robotic tone, uniform sentence length, generic wording — that contributed to the score.
Human Likelihood Score
Alongside the AI probability, shows how many signals point toward human writing — variation, specificity, natural flow, and original phrasing.
False Positive Warning
Clearly flags that results are probabilistic. Clear, simple human writing can sometimes score higher than expected — always apply human judgment before acting on a score.
How AI Detection Works
AI language models generate text by predicting the most probable next word at each step. This produces writing that is statistically smooth — it flows well, avoids unusual word choices, and maintains consistent sentence structure throughout a passage. Human writing, by contrast, is less predictable: humans make stylistic choices, vary sentence rhythm, use specific personal references, and write with what researchers call burstiness and perplexity.
Perplexity measures how unpredictable a piece of text is. High perplexity suggests human writing — the word choices are less obvious. Low perplexity suggests AI writing — the text is statistically predictable. Burstiness measures whether sentence lengths vary significantly. Human writing tends to mix short punchy sentences with longer complex ones. AI writing often keeps sentence lengths similar throughout a passage.
AI detectors score text against these signals and return a probability. A high AI score means the text closely matches AI writing patterns. A low AI score means it resembles human writing. Neither result is guaranteed to be correct — false positives (human text flagged as AI) and false negatives (AI text that passes as human) are both well documented.
Likely Human
Uncertain
Likely AI
Writing patterns match human writing. Low AI signal detected.
Mixed signals. Could be AI-assisted or heavily edited AI output.
Strong AI writing patterns. Human review and editing recommended.
How SEOLark AI Content Detector Works
Paste your text into the input field — a minimum of 100 characters is required for meaningful analysis, and 300 or more words produces the most reliable results. Click Detect AI Content and the tool analyzes the writing against multiple AI signal patterns in seconds.
Paste Your Text
Paste up to 10,000 characters of content. Blog posts, articles, emails, product descriptions, and academic drafts all work. Longer samples produce more accurate results.
Run the Analysis
Click Detect AI Content. The tool scans for AI writing signals including sentence variation, repetitive phrasing, generic wording, robotic tone, and word-choice predictability.
Read the Score and Signals
Review the AI probability score, confidence level, and individual signal breakdown. Each signal explains what pattern was detected and whether it points toward AI or human writing.
Improve and Republish
Use the signal list to guide editing. Sections flagged for robotic tone or repetitive phrasing can be rewritten using the AI Humanizer or edited manually before publishing.
What This Tool Checks
The AI Content Detector evaluates multiple writing signals across the full text. Each check contributes to the overall AI probability score and appears as an individual item in the signal breakdown.
| Check | What It Detects | Status |
|---|---|---|
| Sentence Length Variation | Whether sentence lengths vary naturally (human) or stay uniform (AI) | Checked |
| Repetitive Phrase Detection | Repeated sentence openers, transitional phrases, and filler expressions used across the passage | Checked |
| Robotic Tone | Flat, impersonal sentence construction with no personality, opinion, or voice variation | Checked |
| Generic Wording | Overuse of vague high-frequency words and phrases common in AI output: "leverage," "delve," "furthermore," "in today's landscape" | Checked |
| Word Choice Predictability | Whether the vocabulary is statistically predictable — a low-perplexity signal associated with AI generation | Checked |
| Readability Score | Reading level and clarity rating — very smooth, highly readable text at consistent difficulty is an AI signal | Checked |
| Low Originality Signal | Text that closely matches common AI phrasing patterns with no specific detail, personal reference, or novel observation | Checked |
| Confidence Level | How strongly the overall signal set supports the AI probability estimate: low, medium, or high confidence | Checked |
| Word Count and Length Warning | Flags if the sample is too short for reliable detection — very short texts produce low-confidence results | Checked |
AI Probability vs Final Proof
AI detection scores are probability estimates — they are not evidence in an academic, legal, or editorial sense. Understanding what a score means (and what it does not mean) is essential before acting on any result.
Google has stated that AI-generated content is not automatically against Search guidelines. The concern is specifically scaled AI content produced mainly to manipulate rankings — not AI content that is useful, accurate, and genuinely written for readers. An AI detection score does not determine whether content violates any policy; only the purpose and quality of the content matters for that assessment.
What a Score Tells You
How closely the writing patterns match AI-generated text. Useful for identifying content that may need editing, humanizing, or more specific detail before publishing.
What a Score Does Not Tell You
Whether the author used AI, whether the content violates any policy, or whether the content will rank. A score is not proof of any specific tool or writing method being used.
False Positives Are Real
Clear, simple human writing — especially technical documentation, legal text, and structured academic writing — can score high for AI probability. Never treat a single score as a final verdict.
Human Review Is Always Required
Use the signal breakdown to identify specific weaknesses — robotic tone, repetitive phrases, generic wording — and apply human editorial judgment to those sections specifically.
Common AI Writing Signals
Knowing what AI writing looks like helps you edit more effectively. These six patterns appear most frequently in AI-generated content and are the signals most likely to raise the AI probability score.
Uniform Sentence Length
AI models produce sentences of similar length throughout a passage. Human writing mixes short, punchy sentences with longer complex ones — often within the same paragraph.
Repetitive Openers
AI frequently starts paragraphs with the same transition words: "Furthermore," "Additionally," "It is worth noting," and "In conclusion" appear in nearly every AI-written draft.
Robotic Tone
AI writing tends to be neutral and impersonal — no personality, no specific opinion, no authorial voice. Content that could have been written about anything, for anyone, often scores high for this signal.
Generic Wording
Certain words appear far more in AI output than in human writing: "delve," "leverage," "seamlessly," "navigate," "in the realm of," "it is crucial to," and "robust" are reliable AI markers.
Low Vocabulary Variation
AI uses the same words repeatedly within a passage because those words are statistically dominant for the topic. Human writers naturally introduce synonyms, slang, and alternative phrasings that vary the vocabulary.
Missing Specificity
AI generates claims without specific supporting detail — no data, no personal experience, no named examples. Human writing tends to include specific numbers, references, or observations that AI cannot fabricate reliably.
How to Improve Content Quality After Detection
A high AI probability score is a starting point for editing — not a reason to discard the content. The signal breakdown tells you exactly which patterns raised the score and where to focus revision effort.
Humanize Robotic Tone
Sections flagged for robotic tone or flat sentence structure benefit most from the AI Humanizer. Paste the flagged paragraph and choose Fluent or Conversational mode to introduce natural sentence rhythm and remove mechanical phrasing.
Replace Generic Phrases
Remove AI filler words — "delve," "leverage," "furthermore," "seamlessly" — and replace them with plain, specific language. Read each flagged sentence aloud. If it sounds like a corporate pamphlet, rewrite it in your own voice with a concrete claim or specific detail.
Check Readability After Editing
After humanizing AI content, paste the revised version into the Readability Checker to confirm the reading level matches your target audience. Heavy editing can shift the reading level in either direction.
Final Grammar and Style Check
Run the edited content through the Grammar Checker before publishing. Rewriting AI content by hand or with a humanizer tool sometimes introduces grammatical errors or awkward constructions that need a final pass.
Check AI Content Free
Paste your text above and get an instant AI probability score, signal breakdown, and confidence rating — then use the results to edit and improve before publishing.