Updated March 2026 · Independent Analysis
GrammarlyvsOpenAI API
Grammarly starts at $12/mo; OpenAI API is free. Both rated 4.7/5 by users.
Grammarlyvs OpenAI API
★ 4.7/5
Only in Grammarly
- ✦ Grammar checking
- ✦ Plagiarism detection
- ✦ Tone suggestions
✓ Free planFrom $12/mo30M+ users · est. 2009
Try Grammarly Free →
OpenAI APIvs Grammarly
★ 4.7/5
Only in OpenAI API
- ✦ GPT-4o access
- ✦ DALL-E 3
- ✦ Whisper speech-to-text
2M+ users · est. 2020
Try OpenAI API Free →Ratings Breakdown
Grammarly
4.7/5 avg
G2 Score4.7/5
Capterra Score4.7/5
G2 Rating4.7/5
OpenAI API
4.7/5 avg
G2 Score4.7/5
Capterra Score4.8/5
G2 Rating4.7/5
Quick Stats
Feature Comparison
Grammarly uniquely offers Grammar checking, Plagiarism detection, Tone suggestions. OpenAI API uniquely offers GPT-4o access, DALL-E 3, Whisper speech-to-text. Both share 0 features.
Feature
Grammarly
OpenAI API
Grammar checking
✓
✗
Plagiarism detection
✓
✗
Tone suggestions
✓
✗
Style improvements
✓
✗
Browser extension
✓
✗
MS Office plugin
✓
✗
Mobile app
✓
✗
Team style guide
✓
✗
GPT-4o access
✗
✓
DALL-E 3
✗
✓
Whisper speech-to-text
✗
✓
Embeddings
✗
✓
Fine-tuning
✗
✓
Assistants API
✗
✓
Batch API
✗
✓
Vision models
✗
✓
Function calling
✗
✓
JSON mode
✗
✓
Streaming
✗
✓
Enterprise tier
✗
✓
Total Features
8
12
Quick Verdict
Independent analysis based on features, pricing, and user ratings
Choose Grammarly if you need:
- ✓ Grammar checking
- ✓ Plagiarism detection
- ✓ Tone suggestions
- ✓ Style improvements
- ✓ Browser extension
Choose OpenAI API if you need:
- ✓ GPT-4o access
- ✓ DALL-E 3
- ✓ Whisper speech-to-text
- ✓ Embeddings
- ✓ Fine-tuning
Pricing Comparison
Grammarly starts at $12/mo; OpenAI API is free.
Grammarly Plans
Free tier available
Free
Free- • Basic grammar
- • Spelling
- • Punctuation
PremiumBest Value
$12/month- • Style suggestions
- • Tone detection
- • Plagiarism checker
- • Full rewrites
Business
$15/month- • Team features
- • Style guide
- • Analytics
- • Priority support
OpenAI API Plans
Paid plans only
Pay per use
Free- • Token-based billing
- • Free trial credit
- • All models available
🔔 Get notified when prices change
❓ Frequently Asked Questions
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