AI Tool Comparison
I Ran Grammarly and Synthesia Side by Side for a Week
Grammarly and Synthesia both claim the writing crown. Here is who actually wins, and why the marketing copy is half the story.
5 min read
Grammarly
AI writing assistant for grammar, clarity, and tone
Grammarly helps users improve grammar, tone, clarity, and writing quality across documents, emails, and daily communication.
Synthesia
AI video platform with avatars and voiceovers
Synthesia helps teams create AI-generated videos from text using avatars, voiceovers, and business-friendly templates.
The honest comparison
I had a deadline and two tools. One of them was going to waste my Saturday.
I put Grammarly and Synthesia through the same writing tasks last month instead of reading another ranked list.
Grammarly catches the typo you would have shipped to a client. Synthesia looks uncanny the moment you stare at the face - that gap showed up the moment I exported the file.
Where they overlap, Grammarly catches the typo you would have shipped to a client. Synthesia makes a talking-head video with an avatar that doesn't yawn. I kept both installed for a reason.
Synthesia makes a talking-head video with an avatar that doesn't yawn. Grammarly treats every sentence like it needs a confidence coach. Neither is broken; they argue about different things.
If you non-native writers and fast emailers, keep Grammarly. If you companies mass-producing training videos, Synthesia is the one. I landed on Grammarly for depth, Synthesia for speed after a week of switching back and forth.
Shipped the work, got paid, moved on. That's the review that matters.
Quick Comparison
| Category | Writing Assistant | Video |
|---|---|---|
| Pricing | Freemium | Paid |
| Best For | Students, Professionals, Writers | Teams, L&D, Marketing departments |
| Shared Tags | No major overlap | |
Why choose Grammarly?
- Official affiliate program available
- Well-known brand with broad appeal
- Useful for students and professionals
Why choose Synthesia?
- Strong for business and training videos
- Easy text-to-video workflow
- Useful for explainers and localization
Final takeaway
Grammarly is a better fit if you want strong support for Writing and Editing. Synthesia may be the better choice if your workflow focuses more on Video and Avatars. The right choice depends on your budget, use case, and preferred workflow.