Unlimited AI Detector & Content Checker
with Sentence-Level Analysis

An AI detector — also called an AI checker or AI content detector — estimates how likely a piece of writing was produced by a large language model such as ChatGPT, GPT-5, Claude or Gemini, rather than written by a person.

It doesn't look for a hidden watermark or a secret label. Instead it reads the text itself for the statistical fingerprints machines tend to leave behind — chiefly how predictable the word choices are and how uniform the sentence rhythm is — and turns that into a likelihood score.

Astra runs that analysis entirely in your browser and shows you the exact sentences and signals behind every flag, so a result is something you can read, question and act on — not just a number. Whether you call it an AI checker, an AI text detector or an AI writing detector, the job is the same: tell you, with evidence, how much of a text looks AI-generated.

The percentage at the top is a likelihood, not a verdict — it answers “is this AI generated?” in terms of probability, not proof. A high score means the writing closely matches patterns typical of AI text; a low score means it reads more like a person wrote it. The colored highlights break that down sentence by sentence, so you can tell whether a whole document or just a few passages look generated, and whether a piece is fully human, fully AI, or a mix.

AI writing no longer comes from one place — so Astra is built to detect AI-generated text from today's most-used models, and it's updated as new ones arrive.

It also handles mixed writing, flagging the specific sentences that read as AI inside an otherwise human draft, so part-AI work doesn't slip through as a single clean score.

People call it an AI text detector, an AI writing checker or an AI content detector — but it's all after the same thing: a reliable read on whether writing is human or machine.

Astra covers that whole space. The analysis and the sentence-level evidence work the same way whatever the format, so you can settle “is this AI or human?” for almost any kind of text.

Astra is a free AI checker you can use as often as you like — and a genuinely private one, because your text never leaves your device.

Independent guides warn that many detectors upload your writing to a server, and some store it or reserve the right to train on it. Astra analyzes your text on your own device, so it is never uploaded, stored, logged or used for training — which matters for unpublished, confidential or personal writing.

No AI detector is 100% accurate, and any tool that claims to be isn't being honest — independent benchmarks have measured popular detectors far below their marketing numbers.

Astra returns a probability rather than a guarantee, and we're transparent about exactly how we test and where the limits are. Read how accurate AI detectors are, or start with how AI detection works.