I Hired a Content Writer and Something Felt Wrong — Here Is How to Actually Check If Text Is AI Generated

The copy landed in my inbox on a Tuesday. Five blog posts, right on schedule, from the freelancer I'd paid upfront. I started reading. Something was wrong — not obviously wrong, but wrong. Too smooth. No personality. Every sentence landed the same way. My client read the first one and messaged me within an hour: "Did you use ChatGPT for this?"

I didn't write it. The freelancer did. But now I had a problem: how do I actually know?

If you've been in that situation — a hiring manager reviewing cover letters, a professor looking at a suspiciously polished essay, or a client who paid for original content and isn't sure they got it — this is for you. Not for bypassing detection. For doing the detecting yourself, and doing it right.

Why Checking If Text Is AI Generated Is Harder Than It Sounds

No single tool is definitive. That's the uncomfortable truth most "AI detector" articles skip. AI detectors analyze statistical patterns — how predictable each word is, how uniform sentence length is, how closely the text resembles what a language model would produce. The problem is that these patterns also appear in formal human writing. An ESL student writing carefully, or a professional following a rigid style guide, can score "AI" on a detector without having touched it. AI detection false positives are more common than most people realize.

So before you run anything through a tool, understand: you're looking for a signal, not a verdict.

What Does an AI Detector Actually Measure?

AI detectors measure two main things: perplexity (how surprising each word choice is, statistically) and burstiness (how much sentence length and complexity varies). Human writing tends to be unpredictable and bursty — we trail off, drop a one-word sentence, then write a long winding clause about something only tangentially related. AI writing is uniform, confident, and predictable.

Most major detectors use variations of this approach. They're trained on large corpora of known human and AI text, then fine-tuned to catch outputs from specific models like GPT-4o and Claude. A 78% AI probability score doesn't mean someone used AI. It means the text resembles AI output statistically. Context matters enormously. If you want to go deeper on the mechanics, how AI detectors work is worth reading before you put serious weight on any score.

How to Actually Check If Text Is AI Generated

Here's the process that actually gives you a real answer:

• Run it through multiple detectors. Don't rely on one. GPTZero, Originality.ai, and WriteMask's free AI detector each use slightly different models. If three tools independently flag the same paragraphs, you have a real signal. If one flags everything and another gives it a pass, you're in ambiguous territory.
• Look at paragraph-level results, not just the overall score. Good detectors show you which sections scored high. AI text clusters — introductions and conclusions are often AI-generated while the middle is human, or vice versa. A paragraph at 96% surrounded by paragraphs at 20% tells you something specific. Everything at 60% tells you almost nothing.
• Check for tells beyond the score. Does the text use phrases like "it's worth noting," "it is important to consider," or "in conclusion, this article has explored"? Does every paragraph have exactly three sentences? Does the vocabulary feel oddly formal for the topic and the person who allegedly wrote it?
• Ask for the process. A genuine human writer can usually show their work — notes, drafts, research tabs, sources they pulled from. AI output has no working notes. That absence is itself a signal.
• Check revision history if you have access. Google Docs will show whether text was typed incrementally or pasted in all at once. Pasted-in text from a blank starting point is a red flag worth noting.

Which Detector Should You Actually Trust?

Use at least two independent tools and treat agreement between them as meaningful. A few things are broadly true: paid tools tend to be more accurate for professional use cases; no tool is reliable for short text under 150 words; all tools struggle with heavily edited AI text. If someone used AI and then rewrote significantly, detection becomes genuinely hard.

WriteMask's free AI detector is a solid starting point for a quick read, especially if you're trying to understand whether something warrants deeper scrutiny before you have a difficult conversation.

What If You're on the Other Side — Falsely Flagged?

This is where things get uncomfortable. AI detectors flag human writing regularly. If you're a student, a freelancer, or anyone whose original work got flagged, being accused of AI use when you didn't is genuinely awful. The same tools people use to check your writing are the same tools creating this problem.

If your writing has been flagged, what to do if accused of using AI covers the practical steps — from gathering evidence to the conversation you need to have. And if you use AI as part of a legitimate writing process and need to ensure your final output reads naturally, WriteMask helps make that happen, with a 93% pass rate across major detectors.

The Honest Bottom Line

To check if text is AI generated: run it through at least two independent detectors, look at paragraph-level flags rather than overall scores, and treat the result as one data point alongside human judgment — not a verdict you can act on alone. High scores on multiple reputable tools, combined with other signals like missing revision history or an inability to show source material, build a real case. A single tool saying 70%? That's a reason to look closer, not to accuse.

The technology is imperfect in both directions. Anyone telling you otherwise is overselling their tool.