AI Grammar Checkers vs Grammarly in 2026: Which One Should You Use?

Grammarly is the name most people already know. The others on this page — Coda One, LanguageTool, ProWritingAid, and Hemingway Editor — are the tools readers usually put next to it.

This page used to report a scored test: planted errors, a detection percentage for each tool, and sections titled "Our Test Results." That test is not something we can stand behind, so the numbers and those sections are gone. What is left is what each product is for. Check the vendor's own pricing page before you rely on a price.

What each tool is for

Grammarly is a writing assistant with a browser extension, tone notes, and, on paid plans, a plagiarism check and a rewrite assistant. The free tier covers basic spelling and punctuation. Style and tone suggestions sit on the paid plan. Text is processed on their servers.

Coda One's grammar checker is a browser page. You paste a draft, it marks grammar and wording, and you edit. It does not include a plagiarism check. The free allowance and the paid plans are on the pricing page. The checker itself is at /grammar-checker.

LanguageTool is a rule-based checker with a browser extension and support for many languages, not only English. There is a self-hosted option, which is the one to look at if the draft cannot leave your own machine.

ProWritingAid is aimed at long-form writers. It offers style reports (repetition, pacing, readability) on top of grammar. The free tier is a short sample; the reports are the paid product.

Hemingway Editor is a style highlighter. It marks long sentences, passive voice, and adverbs. It is not a full grammar checker. The web version is free to try; the desktop app is a one-time purchase.

How to choose

• You write in several languages. Start with LanguageTool. The others here are built for English.
• You want the check inside Gmail, Docs, or the browser. Grammarly and LanguageTool both ship extensions. Coda One is a page you paste into.
• You are editing a novel or a long essay and want style reports. ProWritingAid is built for that job. Hemingway is the lighter version of the same idea.
• The draft is confidential. Prefer a tool you can run locally. LanguageTool documents a self-hosted install. A hosted checker, including ours, sends the text to a server.
• You only need a second pair of eyes on grammar. Any of the grammar tools above can be a first pass. None of them replaces a person on a contract, a paper, or a page that has to be right.

What we are not claiming

We have not published a count of errors caught, a false-positive count, or a head-to-head accuracy figure for these tools. A sentence on this page that used to say we had is withdrawn. If a number matters, it has to come from the vendor's own documentation or from a study you can read, not from a test we describe here.