Grammarly Review: Still Worth It in the Age of AI?

Here’s a question we’ve been asked more than any other in the past year: “Why would I pay for Grammarly when ChatGPT can check my writing for free?”

It’s a fair question. We asked it ourselves. So we ran Grammarly on every piece of real client work we produced for six weeks — emails, blog posts, proposals, social copy — alongside the AI chatbots we already use. The answer surprised us.

Grammarly isn’t competing with ChatGPT. They do fundamentally different jobs. And Grammarly is still excellent at the job it actually does.

What Grammarly Does (and What It Doesn’t)

Grammarly is a real-time writing assistant. It sits in your browser, your desktop apps, and your phone keyboard, watching everything you type and flagging errors, awkward phrasing, and tone issues as you write.

That last distinction matters. Grammarly works while you write. ChatGPT and Claude work before or after you write. You paste text into a chatbot and ask it to improve your draft. You don’t paste text into Grammarly — it’s already there, underlining problems as they happen.

This is a fundamentally different workflow, and it’s the reason Grammarly remains relevant. You don’t stop writing to context-switch into another tool. The corrections appear inline, in the same window where you’re already working. For the dozens of short-form pieces most professionals write each day — emails, Slack messages, quick social posts, form responses — this real-time approach is dramatically more practical than copying text into a chatbot.

Grammarly does not write content for you. It has an AI writing feature now (GrammarlyGO), but frankly, it’s not competitive with ChatGPT or Claude for content generation. That’s fine. Grammarly’s value isn’t in generating text — it’s in making the text you’ve already written cleaner, clearer, and more professional.

Our Testing Methodology

For six weeks, we used Grammarly Premium on every piece of client-facing communication our team produced. This included:

• 124 client emails (ranging from brief follow-ups to detailed project updates)
• 18 blog posts (1,000–3,000 words each)
• 32 social media posts (Twitter/X, LinkedIn)
• 8 client proposals (3,000–5,000 words each)
• Dozens of Slack messages, Notion documents, and form responses

We tracked three things: errors caught that we would have missed, false positives (correct writing flagged as wrong), and suggestions that genuinely improved the text versus those that were unhelpful or style-preference differences.

The Browser Extension Experience

The browser extension is Grammarly’s killer feature. Install it once, and it works across Gmail, Google Docs, LinkedIn, Twitter/X, WordPress, Notion, and virtually every other web-based tool you write in.

During our testing, the extension activated correctly on every platform except Figma (which doesn’t support text input extensions) and a custom internal tool built on an older framework. That’s an impressive hit rate. It adds a small Grammarly icon in the corner of text fields, and underlines issues in real time as you type.

Performance impact was negligible. We monitored browser memory usage with and without the extension active and found no meaningful difference on Chrome or Firefox. Page load times were unaffected. This matters because browser extensions that slow things down get uninstalled fast — Grammarly stays out of your way.

The one annoyance: Grammarly occasionally conflicts with other browser extensions that modify text fields, particularly password managers and some CMS plugins. We experienced this with our WordPress editor once, where Grammarly’s suggestions would briefly flash and disappear. Disabling Grammarly on that specific site (which you can do per-domain) solved it immediately.

What the Free Plan Catches

Grammarly’s free plan is, genuinely, one of the best free tools we use. It covers:

• Spelling errors — including contextual misspellings (e.g., “their” vs “there”)
• Basic grammar — subject-verb agreement, punctuation, article usage
• Punctuation — comma splices, missing full stops, incorrect semicolons

During our six-week test, the free-tier features alone caught an average of 3.2 errors per email and 12–15 errors per blog post. Most of these were minor — a misplaced comma, a missing article, a typo — but they’re exactly the kind of errors that make professional communication look sloppy.

Would we have caught them by proofreading? Probably most of them. But Grammarly catches them in real time, before you press send, without requiring a separate proofreading step. That’s the value.

What Premium Adds

The Premium plan (£10/month billed annually) adds three meaningful features:

Clarity and Conciseness Suggestions

This is the feature that justifies the upgrade for professional writers. Premium flags wordy phrases, passive voice, unclear antecedents, and unnecessarily complex sentences. During our test, approximately 40% of Premium’s suggestions in this category genuinely improved the text.

The other 60% were either stylistic preferences (Grammarly tends to prefer shorter sentences, which isn’t always appropriate) or context-dependent suggestions where the original phrasing was actually better. You learn quickly which suggestions to accept and which to ignore.

Tone Detection

Grammarly analyses the overall tone of your writing and displays it as a label — “formal,” “friendly,” “confident,” “concerned,” and so on. This sounds gimmicky, but it’s surprisingly useful for professional communication.

We caught ourselves sending an email that Grammarly flagged as “demanding” when we intended it to be “direct.” Reading it back, Grammarly was right — the tone was off. We rewrote two sentences and the tone shifted to “confident.” It’s a small thing, but for client-facing communication, tone matters enormously.

The tone detection works best on emails and messages of 50+ words. On shorter texts, it doesn’t have enough context to be reliable.

Plagiarism Checker

Premium includes a plagiarism checker that scans your text against a database of web pages and academic papers. It’s useful as a quick sanity check, particularly if you’re working with freelance writers or publishing content that needs to be original.

However, it’s not in the same league as dedicated plagiarism tools like Turnitin or Copyscape. The database is smaller, the matching is less granular, and it doesn’t check against academic databases as thoroughly. For professional publishing, it’s a decent first pass, not a final check.

Grammarly Business

The Business plan (£11/month per member, billed annually, minimum 3 seats) adds team management features: a shared style guide, brand tone profiles, analytics across the team, and admin controls.

We haven’t tested this at length because our team is small enough that we don’t need centralised writing governance. But for businesses with 10+ people writing client-facing content, the style guide feature alone could be worth the cost. It lets you define company-specific terminology, preferred spellings, and tone guidelines that apply across every team member’s Grammarly instance.

At £11/month per member, the pricing is steep for small teams. Three seats minimum means you’re paying at least £33/month before anyone writes a word. For small businesses, the Premium plan at £10/month per individual is the better starting point.

Pricing

Monthly billing is available at roughly 40% higher cost. We’d recommend annual billing if you’re committed — Grammarly is the kind of tool you either use daily or not at all, so a month-to-month trial doesn’t make much sense.

Grammarly vs ProWritingAid: The Brief Comparison

ProWritingAid is the main alternative, and it’s worth mentioning because it’s significantly cheaper (roughly £8/month, or a one-time lifetime purchase for around £200).

ProWritingAid is the stronger tool for long-form writing. Its reports — on sentence structure, pacing, dialogue, and readability — are more detailed than anything Grammarly offers. If you’re writing novels, academic papers, or long-form journalism, ProWritingAid deserves serious consideration.

But for everyday professional writing — emails, short documents, social media, proposals — Grammarly wins on convenience. The browser extension is smoother, the interface is cleaner, and the real-time suggestions are faster and less intrusive. Most professionals aren’t writing novels; they’re writing emails. Grammarly is built for that reality.

Who Grammarly Is For

It’s worth it if:

• You write client-facing content daily (emails, proposals, social posts)
• You want error-checking that works everywhere without changing your workflow
• Tone and professionalism matter in your communication
• You manage a team that needs consistent writing quality

Skip it if:

• You primarily write long-form content and want detailed structural feedback (consider ProWritingAid)
• You’re looking for an AI content generator (use ChatGPT or Claude instead)
• You write almost exclusively in a platform with built-in spelling and grammar checking
• Budget is extremely tight and the free plan covers your needs

The AI Elephant in the Room

Yes, you can paste your email into ChatGPT and ask it to “fix any errors.” We’ve done it. It works. But here’s what that workflow actually looks like: you write an email, copy it, switch tabs, open ChatGPT, paste the text, type a prompt, wait for the response, read the corrected version, copy the relevant bits, switch back to your email, paste the corrections in.

For a blog post, that workflow is fine. For the thirty-seventh email you’re writing today at 4pm? Nobody does that. They just press send and hope for the best.

Grammarly eliminates the hope. The corrections are there, inline, before you press send. No tab-switching, no prompting, no waiting. That’s the entire value proposition, and it holds up even in a world full of AI chatbots.

The two tools are complementary, not competitive. Use Claude or ChatGPT to draft and restructure content. Use Grammarly to catch the errors in everything else you write throughout the day. That’s the workflow we’ve settled on, and it works.

The Verdict

Grammarly remains the best real-time writing assistant available. The browser extension is seamless, the free plan is genuinely useful, and the Premium suggestions for clarity and tone are worth the £10/month for anyone who writes professionally.

It’s not an AI content generator, and it shouldn’t be evaluated as one. It’s an AI editor — a tool that makes your existing writing cleaner and more professional without requiring you to change how you work. In a world where every other AI tool demands that you learn a new workflow, Grammarly’s invisible, just-works approach is refreshingly practical.

The free plan is one of the best free tools in our entire recommended stack. Install the browser extension today and see for yourself. If you find yourself accepting suggestions regularly, the Premium upgrade will feel obvious.