Grammarly's free tier is the most-used grammar checker on earth, and Premium is $12/mo billed annually ($30 month-to-month). Most comparisons of the two tiers cover essays and business mail. This one covers the text developers actually write - and where both tiers behave the same way.
What Free Actually Includes (2026)
- Basic grammar, spelling, punctuation - unlimited words
- 100 AI prompts per month
- Browser extension, web editor, desktop app
What Premium Adds
- Full-sentence rewrites, clarity and tone suggestions
- Plagiarism detection and AI detection
- 2,000 AI prompts per month, 7-day trial
The Part Every Comparison Skips: Code
On both tiers, Grammarly's engine treats your document as prose:
| Input | Grammarly Free | Grammarly Pro |
|---|---|---|
userId in a sentence |
Often flagged | Often flagged |
npm run build --watch |
Flagged as fragment | Flagged as fragment |
| Fenced code blocks | Scanned by extensions | Scanned by extensions |
| Plagiarism / AI detection | Locked | Unlocked |
Premium unlocks features; neither tier has a model of what code is. Upgrading fixes your word count and unlocks detection - it does not stop false positives on identifiers.
The Decision Rule
Prose all day? Free is genuinely usable; Premium pays off when you want tone control and detection. Documents that mix code and prose - READMEs, PR descriptions, docs? A code-aware checker such as Lint skips code by design on its free tier (10 checks a day, no signup), which is the gap neither Grammarly tier covers. BYOK mode is free entirely if you have an API key.
Try Lint's grammar checker - and keep your userIds untouched.
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