Free Grammarly alternative for readability scoring

Grammarly grades grammar. Readability Check grades reading level. The two answer different questions about the same draft. Grammarly reports one readability score, based on the Flesch reading-ease test. Readability Check shows six formulas plus a consensus grade for $0, with no signup. Here is what each tool does, where they overlap, and when to use which.

Last updated 8 October 2026

Side-by-side comparison

Details about Grammarly come from its own plans, support and blog pages, read on 8 October 2026.

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 suggests tightening long or wordy sentences; readability scorers penalise them numerically.
• Plain word choice. Grammarly suggests simpler wording; readability scorers reward words with fewer syllables.
• Active voice. A grammar checker may flag passive voice as a style issue. Readability formulas do not penalise it directly, but active voice usually shortens sentences, which improves the score.

The non-overlap is bigger. Grammarly reports one readability score in its Performance panel, on a 0 to 100 scale. It does not report a school grade level. 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. Grammar checking is Grammarly's core job, and it catches mistakes that are easy to miss in your own draft.
• Tightening prose for tone. The Pro plan can adjust your tone and rewrite full sentences. You won't agree with every suggestion, but the ones you accept can tighten a draft.
• Consistency across documents. Grammarly's Pro and Enterprise plans include a style guide. A readability scorer has nothing like it.

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 is an online application and needs an internet connection to analyse your text. 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. Readability Check has no paid plan. All six formulas, the consensus grade and the audience presets cost nothing.

A practical two-tool workflow

The two tools work well together. 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.

Grammar checking and multi-formula readability scoring cover different problems, so the pair catches more than either tool alone.

Does this matter for SEO?

Only indirectly. Google does not see which tools you used. It sees the page you publish. Neither a grammar score nor a readability score is a ranking signal that we know of, and we have no data showing that either one moves rankings.

What both tools do is make a page easier for people to read: fewer errors, and a reading level that fits the audience. That is worth doing for readers, whatever it does for search.

Frequently asked questions