# AI Writing Pattern Checker — Stylometric Analysis

> Measure sentence-length variance, vocabulary richness, marker phrases and typographic tells, with per-sentence scoring.

This tool measures the stylistic properties that distinguish generated prose from drafted prose: sentence-length variance, moving-average vocabulary richness, the density of marker words and discourse phrases, triadic phrasing, paragraph uniformity, contraction rate and typographic tells. It reports each measurement with its human baseline and scores every sentence, but deliberately states no verdict — stylometry cannot prove authorship.

**URL:** https://convertto.tech/t/ai-writing-pattern-checker
**Category:** AI & LLM Tools (https://convertto.tech/c/ai-tools)
**Privacy:** Runs entirely in the browser; no upload
**Cost:** Free, no sign-up
**Last updated:** 2026-08-01

## Key facts

- **Signals measured:** 7 — variance, vocabulary, markers, typography, triads, paragraphs, contractions
- **Minimum text:** 40 words, though 200+ gives a far more stable reading
- **Verdict:** None. The tool reports measurements and their baselines, not a judgement
- **Privacy:** Runs entirely in your browser — nothing is uploaded
- **Cost:** Free, unlimited, no sign-up

## How to use

1. Enter or paste your text.
2. Press Run, then download the result when it is ready.

## FAQ

### Can this prove text was written by AI?

No. Nothing can, and the tools that claim a percentage are overstating what stylometry supports. Every signal measured here is also produced by careful editing, by formal registers, by non-native English writers and by anyone taught the same essay structure a model was trained on. Published false-positive rates are high enough that acting on a score alone — in grading, hiring or moderation — is indefensible.

### What is burstiness?

The variation in sentence length across a piece of writing. Human prose alternates between long and short sentences much more than generated prose does — a coefficient of variation near 0.55 is typical for people, and near 0.30 for models. It is the single most durable of these signals because it survives light editing.

### Why does it flag em dashes?

Because a plain textarea produces a hyphen and a generator produces an em dash. It is deliberately weighted very low, since word processors, publishing tools and anyone with a compose key produce them too. It is a hint, not evidence.

### What is the difference between this and the on-device detector?

This one is pure arithmetic over the text and runs instantly. The on-device detector loads a real language model and measures how predictable your text actually is to it — the perplexity method the published research uses. They measure different things and are worth reading together.

## Sources

- [Type-token ratio and the moving-average variant (MATTR)](https://www.tandfonline.com/doi/abs/10.1080/09296971003643098) — Journal of Quantitative Linguistics

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