A free alternative to Grammarly for the readability side

Grammarly grades grammar. This tool grades reading level. The two answer different questions about the same draft, and most professional writers use both — Grammarly to catch the errors you cannot see, a readability scorer to confirm the writing reaches the audience you wrote it for. Here is what each tool does, where they overlap, and when to use which.

The two tools answer different questions

Grammarly and a readability scorer look at the same paragraph and report on different aspects of it.

Grammarly is a grammar and style checker. It looks at every sentence and flags errors: subject-verb agreement, comma splices, dangling modifiers, awkward phrasing, weak verbs, repetitive sentence openers, tone mismatches. Its job is to make individual sentences mechanically correct and stylistically tighter.

A readability scorer is a reading-level calculator. It looks at the whole passage and reports a grade level: how many years of education does the average reader need to understand the text on the first pass? Its job is to tell you whether your audience can decode the writing, not whether each sentence is grammatically correct.

Both jobs matter. A passage can score grade 8 on Flesch-Kincaid (well-suited for a general audience) while containing three comma splices Grammarly would catch. A passage can be grammatically immaculate while scoring grade 14 and excluding most of the intended audience. The two failure modes are independent.

Where they overlap

The overlap is small but real. Both tools indirectly reward:

• Shorter sentences. Grammarly flags long sentences as "complex" or "wordy"; readability scorers penalise them numerically.
• Plain word choice. Grammarly suggests simpler alternatives for "complex phrases"; readability scorers reward shorter syllable-count words.
• Active voice. Grammarly Premium flags passive voice as a style issue; readability scorers do not directly penalise it but active voice usually shortens sentences, which improves the score.

The non-overlap is bigger. Grammarly does not measure overall reading grade level (except in the Premium document-statistics panel, which reports one formula). A readability scorer does not catch grammar errors, awkward word order, or tone mismatches.

When Grammarly is the right tool

Three scenarios:

• Catching errors you cannot see. Comma splices, run-ons, agreement errors, missing prepositions. Grammarly's grammar engine is genuinely strong and catches mistakes most writers miss in their own drafts.
• Tightening prose for tone. The Premium suggestions for clarity, engagement, and tone are useful even when you disagree with about half of them — the half you accept usually improves the draft.
• Cross-document consistency. Grammarly enforces team style guides at the document level. A readability scorer does not.

When a readability scorer is the right tool

Five scenarios where Grammarly will not get you what you need:

• Hitting an audience grade level. If your job is "patient information must read at AMA grade 6" or "this insurance disclosure must clear plain-language standards," Grammarly cannot tell you whether you hit it. A multi-formula scorer with audience presets can.
• Auditing a corpus. Scoring 50 PDFs of governance documents to find the worst offenders — Grammarly is a per-document workflow; a multi-formula calculator gives you a number per document quickly.
• Comparing drafts. "We dropped grade level from 12.4 to 8.1" is a defensible, citable statistic. Grammarly's grammar count is not.
• Working with sensitive content. Grammarly transmits the text you write to its servers. A client-side calculator (like this one) runs entirely in your browser — useful for unpublished drafts, internal policy text, medical records, and other content where you do not want to send the words anywhere.
• Working for free. Grammarly Premium is roughly USD 12/month at the standard tier; the document-statistics readability score requires Premium. A free multi-formula calculator covers the readability use case at zero cost.

Side-by-side

A practical two-tool workflow

The teams that take readability seriously usually combine both tools. A working pattern:

1. Draft. Write in your editor of choice — WordPress, Google Docs, Word, Notion.
2. Grammar pass with Grammarly. Catch the errors, accept the tightening suggestions you agree with, reject the ones that flatten your voice.
3. Readability pass with a multi-formula scorer. Paste the cleaned-up text into the home calculator, set the audience preset, and confirm the consensus grade falls in target. Use the sentence-level highlighting to find the rewrites that move the score the most.
4. Re-edit if needed. If the readability pass surfaces problems, fix them. Re-run Grammarly briefly on the rewritten sections; the readability pass often introduces small grammar issues the grammar tool catches in a second sweep.
5. Publish.

Most professional content marketing teams use roughly this two-tool workflow. The combination of grammar checking plus multi-formula readability scoring is much stronger than either tool alone.

Does this matter for SEO?

Yes, indirectly. Google does not see Grammarly or any readability tool — Google sees the rendered HTML. But both tools push the writing toward properties Google's quality raters and engagement metrics reward:

• Grammar cleanliness correlates with quality-rater "expertise" assessments and reduces the bounce-back-to-search pattern Google reads as a failed page.
• Appropriate reading level correlates with dwell time and scroll depth. A page that reaches its audience holds attention longer; a page above its audience pogo-sticks.

For SEO content specifically, the practical standard is: clean grammar plus reading level appropriate to the audience. Grammarly handles the first; a readability tool handles the second.

Frequently asked questions