Grammarly vs ChatGPT: Polish What You Wrote, or Draft It

The short answer: if your team's problem is copy that does not exist yet, ChatGPT is the tool, at $20 a month per person for Plus on monthly billing, or $25 per seat monthly and $20 billed annually on Business for teams of 2 or more (ChatGPT Plus, OpenAI business pricing). If the problem is copy that exists but keeps breaking the brand's rules, Grammarly is the tool: Pro costs $144 per member a year, $12 a month on average, or $30 on monthly billing, with a shared style guide and brand tone (Grammarly pricing article). Both checked on 26 October 2026.

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Plenty of teams pay for both and use each for half the job. That is not waste if the halves are clear: one writes the first draft, the other catches what the first draft and its human editor missed. Grammarly is now part of Superhuman, alongside Superhuman Go, Mail and Docs, and its agents run in Superhuman Go (Superhuman entry, agent builder article).

Where to start:

1. Price the people. For example, a team of six on Grammarly Pro billed yearly pays 6 x $144 = $864 a year; the same six on ChatGPT Business billed annually pay 6 x $20 x 12 = $1,440 (Grammarly pricing article, OpenAI business pricing).
2. Begin with the brand book you have. Its naming page becomes Grammarly style rules; its tone page becomes the instructions of a shared ChatGPT project. Nothing new needs writing to test either.
3. Count corrections, not impressions. Before the trial, note how many edits your reviewer makes to a typical post. Recount after a month.

The plans in one table

From the Grammarly plans page, the Grammarly pricing article, the ChatGPT Plus article and OpenAI's business pricing.

Where they split

Inside the sentence, or before it

Grammarly works where you are already typing, in every app and tab by its own description, and suggests changes to text that exists: corrections, full-sentence rewrites, tone shifts (Grammarly homepage, plans). ChatGPT starts from an empty box and a request. A writer who knows what to say and wants it said cleanly lives in the first; a writer facing a blank brief lives in the second.

Rules the whole team shares

Grammarly turns a style guide into rules that fire for everyone on the plan, one style guide and one brand tone on Pro, unlimited on Enterprise (plans page), and its style rules can be imported from a CSV (style rules). ChatGPT's equivalent is softer: a project holds files and instructions that steer every chat inside it, and Business adds shared projects (Projects, business pricing). Instructions guide a draft. Rules flag a mistake. For product names that must never be misspelt, the flag is the stronger tool.

What happens to the text

On Business, OpenAI does not train on your business data by default (business pricing). On Plus, OpenAI may use conversations to improve its models unless you opt out in data controls (ChatGPT Plus). If drafts carry unreleased product news, that setting decides which plan your team can use.

The agent step: a ChatGPT project drafts, Grammarly catches the slips

Create a project in ChatGPT, upload the brand book and last quarter's three strongest posts as files, and write project instructions: tone, banned phrases, who the reader is (Projects). Project instructions override personal ones inside the project, so every draft starts from the same brief. Ask for a LinkedIn post from this week's release note.

Then the human step. A writer edits the draft into something they would sign, with Grammarly running in the same window so the style rules flag product names, banned words and tone drift as they type. The person decides each suggestion; nothing posts until they have read it out loud once. ChatGPT drafts, Grammarly checks against your rules, a person publishes.

A free week first

Grammarly's Free plan corrects and detects tone with 100 AI prompts a month, and the free version of ChatGPT is open to everyone (Grammarly plans, business pricing FAQ). Give two writers both free tools for a week on real work and count the reviewer's corrections against last week's.

Grammarly's own door to Pro is a trial that asks for $0 today and sends an email reminder 2 days before it ends (plans page). The reminder is courteous, and it also tells you the default after the trial is a paid seat. Put the end date in the diary on day one, with the correction count you need to see by then.

Drafting, checking, or both

Choose Grammarly if your job is keeping many writers consistent with one set of brand rules, in every app they already write in.

Choose ChatGPT if your job is getting from a blank brief to a usable first draft quickly, with research, files and images in the same place.

Choose both if your team does both, in that order: draft, then check. The Grammarly entry covers its plans, and how to use Grammarly sets up style rules and a brand tone for a marketing team. ChatGPT has no entry here; its site is chatgpt.com.

FAQ

Is Grammarly part of Superhuman now?

Yes. Grammarly's support pages say it is now part of Superhuman, a suite that includes Superhuman Go, Grammarly, Coda and Superhuman Mail (pricing article).

Can Grammarly spot AI-written text?

Grammarly Pro lists detection of plagiarism and AI-generated text among its features (plans page). Treat any detector's verdict as a reason to ask the writer, not as proof.

Can ChatGPT be billed yearly for one person?

No. OpenAI's help centre says Plus has no annual billing; annual plans exist for Business and Enterprise (ChatGPT Plus, business pricing).