7 Best Grammar Checkers for Mac in 2026
We tested every major grammar checker on macOS — from system-wide native apps to browser extensions and AI-powered tools. Here are the 7 best options for Mac users, ranked by accuracy, speed, privacy, and real-world usability.
What We Tested
Mac users have unique needs. Unlike Windows, macOS has a rich native app ecosystem — but most grammar checkers are built for browsers first and Mac second. We tested each tool on three criteria:
- System-wide support — Does it work in every app, or just browsers and Google Docs?
- Accuracy — We ran 50 sentences with common grammar errors through each tool
- Privacy — How is your text data handled?
Quick Comparison
| Tool | System-Wide | Price | Privacy | Best For |
|---|---|---|---|---|
| FlowWrite | All Mac apps | Free / $2.99/mo | No data stored | System-wide correction |
| Grammarly | Limited | Free / $12/mo | Stored | Browser writing |
| LanguageTool | Some apps | Free / $5/mo | Self-host option | Multilingual |
| ProWritingAid | Limited | Free / $10/mo | Stored | Long-form writing |
| Apple Writing Tools | Apple apps only | Free | On-device | Basic corrections |
| QuillBot | Browser only | Free / $10/mo | Stored | Paraphrasing |
| Hemingway | Own editor | $10 one-time | On-device | Readability |
1. FlowWrite — Best System-Wide Grammar Checker for Mac
FlowWrite is a lightweight menu bar app that works in every Mac application. Select any text, press Tab, and AI corrects grammar, translates, or adjusts writing style — replacing the text in place.
Why We Picked It
- True system-wide support — works in Mail, Slack, VS Code, Notes, Chrome, Safari, Discord, and literally any app with text
- 5 modes — Grammar correction, translation, shortening, expanding, and style adjustment
- Privacy-first — text is sent for correction only, never stored or used for training
- Fast — corrections in under 2 seconds
- Generous free tier — 10 corrections/day with all features, no account needed
Limitations
- macOS only (no Windows, no web)
- Requires Accessibility permission
Price: Free (20/day) or $2.99/month (1,000/day). Download FlowWrite →
2. Grammarly — Best for Browser-Based Writing
Grammarly is the most well-known grammar checker with over 30 million users. It excels at browser-based writing with Chrome and Safari extensions, and has a dedicated Mac app.
Pros
- Excellent grammar detection accuracy
- Tone detection and style suggestions
- GrammarlyGO AI assistant for rewriting
- Integrations with Google Docs, Microsoft Office
Cons
- Desktop app doesn't work in all Mac apps — limited to supported integrations
- Free tier is very limited (basic grammar only)
- Privacy concerns — text is processed and stored on Grammarly servers
- Premium is $12/month (annual) or $30/month (monthly)
- Can be resource-heavy
3. LanguageTool — Best Open Source Option
LanguageTool is an open-source grammar checker that supports 30+ languages. It has a Mac desktop app and browser extensions. A strong choice for multilingual writers.
Pros
- 30+ languages supported
- Open source — you can run it locally
- Good Mac desktop app with some system-wide support
- Affordable at $5/month
Cons
- AI features only in premium tier
- Desktop app doesn't work in all applications
- Less polished UI than Grammarly
4. ProWritingAid — Best for Creative Writers
ProWritingAid goes beyond grammar checking with deep writing analysis — readability scores, pacing, sentence variation, and manuscript-level feedback. Ideal for novelists and long-form writers.
Pros
- Manuscript analysis and chapter critique
- 20+ writing reports
- One-time lifetime purchase option
- Integrations with Scrivener
Cons
- Limited system-wide support on Mac
- Slower corrections than competitors
- Steeper learning curve
5. Apple Writing Tools — Best Built-In Option
Apple introduced Writing Tools in macOS Sequoia, offering basic proofreading, rewriting, and summarization powered by Apple Intelligence.
Pros
- Free and built into macOS
- On-device processing for privacy
- Works in Apple apps (Mail, Notes, Pages, Safari)
Cons
- Only works in Apple's own apps and some third-party apps
- Grammar correction is basic — misses many errors
- Rewrite feature often changes meaning
- Requires Apple Silicon Mac with 8GB+ RAM
- English-only for most features
6. QuillBot — Best Free Option
QuillBot is primarily a paraphrasing tool that also offers grammar checking. It works entirely in the browser with a generous free tier.
Pros
- Excellent paraphrasing with multiple modes
- Generous free grammar checking
- No account required for basic use
Cons
- Browser-only — no Mac app
- Grammar checking is secondary to paraphrasing
- No system-wide support
7. Hemingway Editor — Best for Readability
Hemingway Editor focuses on making writing clear and concise. It highlights complex sentences, passive voice, and adverbs — but it's not a traditional grammar checker.
Pros
- Beautiful, distraction-free editor
- Readability grade scoring
- One-time purchase ($10)
- Works offline
Cons
- Not a grammar checker — focuses on style only
- Must copy text into Hemingway's own editor
- No system-wide integration
Our Verdict
For Mac users who want grammar correction that works everywhere — not just in browsers or specific apps — FlowWrite is the clear winner. Its system-wide approach means you can fix grammar in any text field on your Mac with a single keystroke.
If you primarily write in browsers, Grammarly remains excellent. For multilingual writers, LanguageTool is hard to beat. For creative writers, ProWritingAid's deep analysis tools are unmatched.
We recommend starting with FlowWrite's free tier (10 corrections/day, no account needed) to see if the system-wide approach fits your workflow.