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Documentation · head to head

Grammarly vs HeyGen

Grammarly logo

Grammarly

Documentation

Great writing, simplified

From
Free
Rated
-
Full reviewWebsite
HeyGen logo

HeyGen

AI

AI video generation with realistic avatars

From
Free
Rated
-
Full reviewWebsite

The short version

  • Each has a real cost: Grammarly occasional false positives and grammatically incorrect suggestions that can introduce errors; HeyGen avatar movements feel unnatural in longer videos and repetitive with limited emotional expression, appearing stiff and robotic after 60 seconds
  • They diverge on capability: Grammarly covers Grammar checking, HeyGen covers AI avatars.
  • Prices and features above were last checked on 30 August 2026.

Where they differ

Only the attributes on which Grammarly and HeyGen actually diverge.

Attributes where Grammarly and HeyGen differ
AttributeGrammarlyHeyGen
PlatformsWeb, macOS, Windows, iOS, AndroidWeb
CategoryDocumentationAI
Founded20092020

Identical on both: starting price (Free), pricing model (Unknown), free tier (Yes), user rating (Not yet rated).

What each one covers

Drawn from each product's published feature list. An absence here means we hold no record of it - not that the product lacks it.

Only in Grammarly

  • Grammar checking
  • Spelling correction
  • Punctuation
  • Clarity suggestions
  • Engagement feedback
  • Delivery insights
  • Plagiarism checker
  • Citation generator

Only in HeyGen

  • AI avatars
  • Text-to-video
  • Voice cloning
  • Video translation
  • API access
  • Zapier
  • CRM integrations
  • Web support

What people use each for

The jobs each tool is most often brought in to do.

Grammarly

  • Email writingnot HeyGen
  • Document editingnot HeyGen
  • Academic writingnot HeyGen
  • Business communicationnot HeyGen
  • Content creationnot HeyGen

HeyGen

  • ai tools managementnot Grammarly
  • Workflow automationnot Grammarly
  • Reportingnot Grammarly

Where each one falls short

Documented limitations, not opinions. Every one is a constraint you would hit in normal use.

Grammarly

  • Occasional false positives and grammatically incorrect suggestions that can introduce errors
  • Privacy concerns about sending text to Grammarly's servers for analysis
  • AI capabilities sometimes produce hallucinations and fabricated citations that appear grammatically correct

HeyGen

  • Avatar movements feel unnatural in longer videos and repetitive with limited emotional expression, appearing stiff and robotic after 60 seconds
  • Cannot reliably choreograph natural interactions like walking through a room, using devices, or drinking from objects
  • Billing gap between marketed unlimited plans and actual credit consumption is highest complaint with lost credits on failed renders
  • Inconsistent lip sync and voice quality with slow processing and occasional moderation blocks without explanation
  • Customer support described as non-existent with no way to complain or reach a human representative

Pricing, plan by plan

Grammarly

Free
  • FreeFree
    • Basic grammar and spelling checks
    • Tone visibility
    • 100 AI prompts per month
  • Pro$12/month
    • Sentence rewrites
    • Tone adjustment
    • Plagiarism and AI detection

HeyGen

Free
  • FreeFree
    • 3 videos
    • With watermark
  • Creator$29/month
    • Unlimited videos
    • 200 monthly credits
  • Pro$99/month
    • 2,000 credits
    • Advanced features

Which should you pick?

Choose Grammarly if

  • You need grammar checking.
  • You want to start without paying.
  • You work on Web, macOS, Windows, iOS, Android.
  • You also want spelling correction.
Grammarly review

Choose HeyGen if

  • You need ai avatars.
  • You want to start without paying.
  • You also want text-to-video.
HeyGen review

Questions people ask

Is Grammarly or HeyGen better?
Neither clearly leads. Grammarly starts at Free and HeyGen at Free, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, Grammarly or HeyGen?
Grammarly starts at Free and HeyGen at Free.
Does Grammarly or HeyGen run on more platforms?
Grammarly runs on Web, macOS, Windows, iOS, Android. HeyGen runs on Web.
Can I use Grammarly for free?
Both have a free tier, so you can try either at no cost before committing.
What is Grammarly best used for?
Grammarly is most often used for email writing, document editing, academic writing, business communication. Of those, email writing and document editing are not what HeyGen is typically brought in for.
What can Grammarly do that HeyGen cannot?
Grammarly covers Grammar checking, Spelling correction, Punctuation, Clarity suggestions. HeyGen covers AI avatars, Text-to-video, Voice cloning, Video translation.

Answered from the vendors’ own pages

Grammarly: Does Grammarly have a free version?

Yes, Grammarly offers a free tier with basic spelling, grammar, and punctuation checks, tone visibility, and 100 AI prompts per month. The Pro plan ($12/month annual) adds sentence rewriting, plagiarism detection, and 2,000 AI prompts.

Source
HeyGen: What are HeyGen's pricing plans?

HeyGen offers Free ($0, 3 videos/month with watermark), Creator ($29/month, unlimited videos + 200 monthly credits), Pro ($99/month, more credits), Business ($149/month + $20/seat, 4K rendering), and custom Enterprise pricing.

Source
Grammarly: What platforms does Grammarly work with?

Grammarly works across 1 million+ apps including Google Docs, Microsoft Word, Outlook, Slack, Gmail, and web browsers. It also integrates with productivity tools like Asana, Jira, Monday.com, Confluence, and HubSpot.

Source
HeyGen: How does HeyGen's credit system work?

HeyGen uses a credit-based system where Avatar IV video costs 20 credits per minute, video translation costs 5-10 credits per minute. Creator includes 200 credits/month, Pro includes 2,000 credits/month, and Business shares 1,000 credits across the workspace.

Source
Grammarly: Can I use Grammarly offline?

Grammarly requires an internet connection to function, though the browser extension works with some offline text areas. For offline use, the desktop app and browser extensions sync when reconnected.

Source
HeyGen: What is Digital Twin and how much does it cost?

Digital Twin creates a custom avatar from 2 minutes of recorded footage. Additional avatar slots beyond the default cost $29/month each.

Source
Grammarly: What is included in the Enterprise plan?

The Enterprise plan includes unlimited team members, dedicated support, custom roles and permissions, data loss prevention, bring-your-own-key encryption, and unlimited AI prompts. Pricing is custom and available by contacting sales.

Source
HeyGen: How many languages can HeyGen translate videos into?

HeyGen can translate videos into 175+ languages with AI lip sync, making it useful for global content distribution and localization.

Source
HeyGen: What do users say about HeyGen's ratings?

HeyGen has 4.8/5 on G2 across more than 1,000 reviews and 4.7/5 on Capterra across 313 verified reviews as of June 2026, with avatar quality scoring 9.2/10.

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