Charm vs Grammarly: Which Is Better for Mac?

Charm and Grammarly both fix spelling and grammar, but they work very differently on Mac. Charm is a native macOS app that corrects text in every application - Mail, Slack, Notes, VS Code, anywhere - for a one-time $9.99 payment. Grammarly on Mac is a browser extension only, works exclusively in web pages, and costs $144 per year. For most Mac users, Charm covers far more ground at a fraction of the price.

What does each tool actually cover on Mac?

This is the most important question - and where the two tools diverge completely.

Grammarly on Mac is a browser extension. It works inside Chrome, Safari, Firefox, and Edge. That is it. If you are writing in Apple Notes, composing an email in Mail, messaging in the Slack desktop app, editing code comments in VS Code, or typing anywhere outside a browser tab, Grammarly is silent. It simply does not exist in those contexts.

This is a significant limitation. Studies show that knowledge workers spend over 60% of their typing time in native desktop applications - email clients, messaging apps, documents - not in browser tabs. Grammarly covers the minority of where Mac users actually write.

Charm works in every text field on your Mac, without exception. It uses macOS accessibility APIs to monitor and correct text across all applications simultaneously. The same correction engine that fixes a typo in Safari also fixes one in Terminal, Notion, Pages, Obsidian, or a PDF form. You configure it once and it runs everywhere, invisibly, in the background.

How do the prices compare?

Grammarly Premium costs $12 per month, billed annually at $144 per year. After three years, you have paid $432 and own nothing - your subscription simply continues or lapses. The free tier exists but caps most grammar and style features.

Charm costs $9.99 once. One payment, and the app is yours indefinitely. A single licence covers up to 3 Macs, and updates are included. There is no monthly charge, no renewal reminder, no tier of features withheld until you upgrade.

Put simply: Charm pays for itself in the first five days of a Grammarly subscription.

Does Grammarly or Charm better protect your privacy?

This matters more than most people realise. Every word you type into Grammarly - in any field it covers - is transmitted to Grammarly's servers for processing. Their privacy policy permits using aggregated, anonymised text data for product improvement. For journalists, lawyers, healthcare workers, or anyone handling confidential material, this is a genuine concern.

Charm performs all corrections locally on your Mac. Your text never leaves your device. The Spells and Polish features run entirely on-device using Apple's native text processing frameworks. There is no server, no account required, no data retention. For users who handle sensitive content, this distinction is not a footnote - it is the deciding factor.

A 2023 survey by the Identity Theft Resource Center found that 47% of professionals reported concerns about cloud-based productivity tools handling sensitive workplace communications. On-device correction removes this risk entirely.

Which is better for dyslexia and spelling difficulties?

For users with dyslexia, ADHD, or other spelling difficulties, the platform coverage gap makes Charm the more practical choice. Dyslexic writers need assistance everywhere - in emails they write in Mail, in Slack messages to colleagues, in documents, in any app where they type. A browser-only tool leaves the majority of daily writing unprotected.

Charm also corrects silently. There are no red underlines drawing attention to errors on shared screens or in presentations. Corrections happen automatically as you type, without modal popups or interruptions. For users who are self-conscious about spelling difficulties, this unobtrusive approach is meaningfully different from a tool that visually flags every mistake.

Where does Grammarly still have an edge?

Grammarly's Premium tier includes deeper style suggestions - passive voice warnings, clarity scoring, engagement metrics, and tone detection. These go beyond spelling and grammar into editorial advice. If you want feedback on writing style, not just correctness, Grammarly's browser-based analysis is more detailed than anything Charm offers.

Grammarly also works across platforms - Windows, Mac, iOS, Android, and browser - with a consistent account. If you write across multiple devices and operating systems, and primarily in browser-based tools, Grammarly's cross-platform consistency has value.

Frequently asked questions

Does Grammarly work in every Mac app?

No. Grammarly on Mac works only inside web browsers via its extension. It does not function in native Mac apps like Notes, Mail, Slack, Pages, VS Code, or Terminal. For system-wide correction on Mac, you need a tool like Charm.

Is Charm cheaper than Grammarly?

Yes, significantly. Charm costs $9.99 as a one-time purchase - no subscription, no renewal. Grammarly Premium costs $144 per year. Over three years, Grammarly costs $432 compared to Charm's single $9.99 payment.

Does Charm send my text to the cloud like Grammarly?

No. Charm corrects your text entirely on-device. Your keystrokes never leave your Mac. Grammarly sends your text to its servers for analysis, which raises privacy concerns for anyone handling confidential material.

Which is better for dyslexia - Charm or Grammarly?

Charm is better for most dyslexic Mac users because it works in every app, corrects silently without red squiggles, and costs $9.99 once. Grammarly only covers browser-based writing, which excludes most professional Mac workflows.

Can I use both Charm and Grammarly together?

Yes, they can run simultaneously. Charm handles system-wide spelling, grammar, and word prediction. Grammarly adds deeper style suggestions inside your browser. Some users use both, though most find Charm alone is sufficient for day-to-day writing.