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 as you type across your Mac, on-device, for a one-time $19.99 payment. Grammarly works in your browser and, through its Mac app, in desktop apps such as Apple Mail, Word and Slack, shows each fix as a suggestion to accept, checks your text on its servers, and costs $144 per year for Premium.

What does each tool actually cover on Mac?

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

Grammarly on Mac comes in two parts. A browser extension covers Chrome, Safari, Firefox and Edge, and a separate Mac app covers desktop apps such as Apple Mail, Word and Slack. In both, Grammarly underlines a problem and waits for you to accept the fix, and your text is checked on Grammarly's servers.

In both, Grammarly underlines a problem and waits for you to choose the fix. That suits careful editing, but in quick emails and messages it means stopping to click on every mistake.

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 across your Mac, 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 $19.99 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 costs less than two months 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 across your Mac - 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.

What does setting each one up involve?

Grammarly needs an account and, on Mac, two installs if you want it outside the browser: the browser extension for each browser you use, and the Grammarly for Mac app, which asks for the Accessibility permission so it can show its button beside text fields in supported desktop apps. You sign in to both. Code editors such as VS Code are not supported, and every check needs an internet connection.

Charm is one download. On first launch it walks you through two macOS permissions (Accessibility and Input Monitoring), your licence key, turning off macOS autocorrect so the two do not both edit the same word, and choosing an engine: Fast (about 1.5 GB, for Macs with 8 GB of memory), Best Quality (about 2.3 GB, for 16 GB) or Built-In Spellcheck with no download. After that there is no account to create and nothing to set per app; code editors start in Manual, where you select text and press Option-Command-V.

Frequently asked questions

Does Grammarly work in every Mac app?

Not every one. Grammarly works in your browser through its extension, and through its Mac app, in desktop apps such as Apple Mail, Word and Slack. It suggests fixes for you to accept and checks your text on its servers. For correction as you type across your Mac, on-device, you need a tool like Charm.

Is Charm cheaper than Grammarly?

Yes, significantly. Charm costs $19.99 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 $19.99 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 corrects as you type without red squiggles or choices to make, works on-device, and costs $19.99 once. Grammarly underlines problems and waits for you to pick the fix.

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.