Best free readability checkers compared

A free readability checker scores your writing with formulas such as Flesch-Kincaid and tells you the school grade needed to read it. The free tools differ in three ways that matter: how many formulas they show, how much text they take, and whether you need an account. This page compares seven of them.

Last updated 8 October 2026

Side-by-side comparison

Every detail about another tool comes from that tool's own page, read on 8 October 2026. "Not stated" means the page didn't say, not that the answer is no.

The seven tools, and what each is best for

Readability Check: best for several formulas with no signup

This is our tool. It shows six formulas at once: Flesch Reading Ease, Flesch-Kincaid, Gunning Fog, SMOG, Coleman-Liau and the Automated Readability Index. It averages them into one consensus grade and colours each sentence by length, so you can see what to rewrite.

You can paste text, fetch a web page, or open a .docx, .pdf or .txt file. Scoring happens in your browser, so the text you paste is never sent to a server. There is no account and no paid tier. You can also pick a target reader, share a report as a link, and compare two drafts.

What it doesn't do: it has six formulas, not eleven or seventeen. It has no Dale-Chall, Spache or Fry score. It doesn't check grammar or spelling, and it doesn't flag passive voice.

Hemingway Editor: best for one simple grade and style edits

Hemingway's readability checker shows the grade level of your writing and highlights sentences that are hard to read. Its page says you can scan "an unlimited amount of text at once", and you can import a file as well as paste.

It gives one grade, not a set of named formulas. That suits you if you want a quick answer and a clear list of sentences to fix. A paid version, Hemingway Editor Plus, is also offered. See our fuller Hemingway comparison.

WebFX Readability Test: best for testing a live web page

The WebFX Readability Test reports six scores: Flesch Reading Ease, Flesch-Kincaid Grade Level, Gunning Fog, Coleman-Liau, the Automated Readability Index and SMOG. You can test a web address, paste text, or upload a .txt, .doc or .docx file.

Its highlight options cover hard sentences, very hard sentences, passive voice and adverbs. That makes it the closest free match to ours on formulas, with style flags we don't offer.

Originality.ai: best for the widest set of free formulas

Originality.ai's readability checker lists eleven formulas. As well as the six common ones, it has Dale-Chall, Spache, Linsear Write, FORCAST and Powers-Sumner-Kearl. It takes pasted text, a web address, or a .docx, .txt or PDF file, and it highlights sentences.

The tool shows a counter of 2,000 words, and the page offers a paid upgrade. Choose it when you need a formula such as Dale-Chall or Spache and your text is short.

Datayze Readability Analyzer: best for Dale-Chall and Fry

The Datayze Readability Analyzer reports Flesch Reading Ease, Gunning Fog, Flesch-Kincaid Grade Level, SMOG, the Dale-Chall score and the Fry readability grade. You can type or paste a passage, or upload a file. Its page says it works best with plain text.

It is a plain, no-frills tool. It is the only free tool on this page that lists a Fry grade.

ProWritingAid: best if you also want grammar help

ProWritingAid's readability checker reports Flesch Reading Ease, Flesch-Kincaid Grade Level, Coleman-Liau and the Automated Readability Index. It also underlines grammar and spelling problems, which most checkers on this page don't.

The limit is the tightest here. Its page says a free account lets you run reports on up to 500 words, and that you need to upgrade for more.

Readable: the paid option, with a free trial

Readable says it scores content with 17 readability algorithms. It also checks spelling, grammar and style, and it can score a document, a web page or a whole website.

It isn't a free tool. The site offers a 7-day free trial and paid plans. We include it because people looking for a free checker often land on it, and because it does more than any free tool here.

How to choose

• You want a number fast. Any of these will do. Hemingway gives the simplest answer: one grade.
• You need to hit a set grade for work. Use a tool that shows several formulas, so one odd score doesn't mislead you. Readability Check, WebFX, Datayze and Originality.ai all do. See what counts as a good score for targets by audience.
• Your text is long. Avoid the 500-word and 2,000-word limits. Use Readability Check or Hemingway.
• Your text is private. Check the tool's privacy policy first. Ours scores text in your browser and never uploads it.
• You write for young children. Look for Spache or Dale-Chall, which were built for that. Originality.ai and Datayze have them. We don't.
• You want grammar fixed too. Use ProWritingAid or Readable. A readability checker alone won't catch grammar errors.

How we checked

We read each tool's own page on 8 October 2026 and recorded only what it said. We did not run timed tests or score the same text in every tool, so this page makes no claim about which tool is most accurate. Tools change. If a detail here is out of date, tell us and we'll fix it.

Two tools can also give different grades for the same text and both be working as designed. Our guide to the readability formulas explains why.

Frequently asked questions