Free AI Content Detector (+ Guide)

What is an AI content detector?

An AI content detector is a tool that scores how much a piece of content shows the habits of AI writing.

For content, the question is rarely "who typed this". It's whether the draft reads like a person who knows the topic, or like a chatbot's average of it.

How to use the AI content detector

It takes a few seconds:

The screenshot below marks two things:

1. The AI score: 35 out of 100 for an AI-sounding outreach email.
2. A tell: "I hope this email finds you well", marked in the text.

Does Google penalize AI content?

It doesn't penalize content for being AI. Google's own guidance opens with this: "Generative AI can be particularly useful when researching a topic, and to add structure to original content."

The same page draws the line: "using generative AI tools or other similar tools to generate many pages without adding value for users may violate Google's spam policy on scaled content abuse."

So the real risk is a page that adds nothing, whatever its score. A detector helps you find the drafts that read that way.

How accurate is it?

To see how far to trust it, I tested it on 100 paragraphs.

Half came from my own posts written from 2013 to 2021, before ChatGPT existed. The other half came from an AI, asked for a paragraph on each of the same titles.

The test has limits. It used one AI model and plain prompts, on short English paragraphs. An AI told to sound human, or edited by a person, slips through more often.

A real example: an AI paragraph and one of mine

Here's how the two ends of my test look in the checker. First, the start of the AI paragraph with the highest score, written for a post on hosting virtual conferences:

It scored 81 out of 100, with 13 tells marked. Most were AI vocabulary like "robust" and "seamlessly", and lists of three.

Then a line from my own post in 2014, about my first year of blogging:

That paragraph scored 0. It's uneven, personal and a little rough, which is how people write.

Why no AI detector is proof

Even OpenAI pulled its own detector. Its page says: "As of July 20, 2023, the AI classifier is no longer available due to its low rate of accuracy."

On OpenAI's own test, it caught 26% of AI text and wrongly flagged 9% of human text.

Detectors can also be unfair. A Stanford study, GPT detectors are biased against non-native English writers, found that "these detectors consistently misclassify non-native English writing samples as AI-generated."

That one matters to me: English isn't my first language, and my 2014 paragraph above scored 0. Still, treat any score as a reason to read closer, never as a verdict.

What to do with a high score

A high score on a draft you paid for is a reason to ask, not to accuse. These steps work:

• Ask how it was written – many writers use AI for an outline, which is fine if the rest is theirs.
• Check the facts – AI drafts often state things nobody checked.
• Look for experience – real examples, numbers and opinions are what readers and search engines reward.
• Rewrite what's left – press Humanize it, then add what only you know.

Then run it through the SEO checker before it goes live.

Who is the AI content detector for?

It's for anyone who publishes or buys content:

• AI humanizer – bloggers fixing a draft that reads like AI
• SEO checker – site owners checking the page before it goes live
• How to start a blog – new bloggers writing their first posts
• AI article writer – writers who want a draft built from the best posts

And if you hire writers, a quick check on the first draft saves a long edit later.