Chrome Spell Check vs a Grammar Checker: What Each One Actually Catches

The short answer

Chrome spell check catches misspelled words and nothing else with any reliability. A grammar checker catches misspelled words plus the categories a dictionary lookup cannot see: wrong-word choices, agreement errors, tense errors, punctuation that changes meaning, and sentences that are grammatical but say something other than what you meant.

The reason for that gap is not laziness in Chrome's implementation. It is the shape of the problem. A spell checker asks one question — is this token in the dictionary? — and 'effect' is in the dictionary. Answering whether 'effect' is the right word in this sentence requires understanding the sentence, which is a different and much harder problem.

What Chrome spell check is, and where the setting lives

Chrome spell check underlines words it thinks are misspelled as you type, in any standard text field on any website. Right-clicking an underlined word shows suggestions from Chrome itself — that menu is Chrome's, and any extension you have installed may or may not add entries to it.

1. 1

   Open Chrome's Languages settings

   Menu (three dots) → Settings → Languages. On some builds the same page is reachable from Settings → You and Google → Languages.

2. 2

   Turn on spell checking

   The section is labelled something close to 'Check for spelling errors'. There is a toggle, and underneath it two options.

3. 3

   Choose Basic or Enhanced

   Basic spell check uses dictionaries stored on your device. Enhanced spell check sends the text you type to Google and uses Google's spelling service. Chrome explains this in the setting itself; the wording has changed across versions.

4. 4

   Add and enable each language

   Spell check only runs for languages that appear in your list with spell check enabled. A field typed in a language you have not added gets no underlines at all, which is the most common cause of 'spell check stopped working'.

   Google documents the current settings path and option names in its Chrome Help article on turning spell check on and off. Setting labels and locations move between versions, so use that page as the source of truth rather than a screenshot in any article.

Basic versus Enhanced: the difference that matters

Most comparisons stop at 'Enhanced catches more'. That is true but it leaves out the part you should actually decide on, which is where your text goes.

The gate on this article from our own editing standard is worth repeating, because it is the claim most comparison articles get wrong: Enhanced spell check is not context-free. It runs a statistical model that sees the surrounding words, and it does sometimes catch a contextual error that Basic waves through. What it is not is a grammar checker. It is optimised for the question 'did this person mean a different word?', and agreement, tense, punctuation and ambiguity are not that question.

The test set, and what each tool did with it

Here is the paragraph we used. It contains one error of each category, plus tokens that should be left alone. Paste it into any plain text field — the address bar search box works, or a blank email draft — and you can reproduce the whole table in about two minutes on your own build.

The client recieved the proposal on friday and the three requirement
in section two was unclear. It will effect the timeline if we dont
clarify them soon. Tomas from Zephra said the eu-west-2 cutover is
scheduled for 12 March, but the contract says 12 April and I think
its the contract date that matters. Lets eat the output first.
Rewrite this shorter. The deployment failed becasue the request-id
header was missing, which validate the JWT incorrectly.

The last row is the one people forget. Chrome spell check flags Tomas, Zephra, eu-west-2, request-id and JWT as misspellings, because they are not in the dictionary. You can add each one manually to Chrome's dictionary, one right-click at a time, and that list is local to your profile and does not travel with you. A grammar checker with a protected-words list handles the same tokens in bulk, and the protection applies to the correction rather than just suppressing the underline.

The gap that costs you the most: valid but wrong

Every error in the table above that Basic misses is an error where all the words are real. That is not a coincidence, it is the whole limitation in one sentence. A dictionary lookup has no way to tell you that 'effect' should be 'affect', because 'effect' is a perfectly good English word.

The categories in this family, and roughly how often they appear in professional writing:

• Homophone pairs: effect/affect, there/their/they're, its/it's, your/you're, then/than, compliment/complement, principal/principle, stationary/stationery.
• Confusable verbs: lie/lay, rise/raise, sit/set, assure/ensure/insure, imply/infer.
• Countability: fewer/less, amount/number, among/between.
• Agreement: 'the list of items are' for 'the list of items is', 'the team have' versus 'the team has', 'each of the reports were' for 'each of the reports was'.
• Tense and participle: 'I have went', 'she had wrote', 'it was ran'.

Punctuation and meaning: the two categories nobody checks

Spell check has no punctuation model at all. It tokenises words and looks them up; commas, apostrophes and full stops are not tokens it evaluates. So every punctuation error you have ever made in a browser text field went past Chrome without a mark, and will continue to.

Missing punctuation is often harmless. Sometimes it changes what the sentence says. The standard example is 'Let's eat, Grandma' versus 'Let's eat Grandma'; a work version that appears constantly in tickets and pull requests is the difference between 'check the output before the deploy finishes' and 'check the output, before the deploy finishes'. Both are grammatical. They give the reader opposite instructions about timing.

Meaning errors are the category where you should hold any tool to a low expectation, including ours. 'Rewrite this shorter' is a grammatical, correctly spelled English sentence that does not tell the reader shorter than what, or which text. No spell checker flags it. A grammar checker may flag it as vague and may not. Automated tools catch structural problems; deciding whether a sentence actually conveys your intent is still reading, and still yours.

Keep Chrome spell check on anyway

This article is not an argument for turning spell check off. For the category it covers it is the best tool available, and it is hard to overstate how good the deal is: it runs as you type, it costs nothing, Basic never leaves your device, it works offline, and it works in every field in every site without an extension.

What it is not is a finishing pass. The red underline disappearing is not evidence your message is correct — it is evidence your message contains no misspellings. Those are different claims, and the second one is much narrower than most people assume.

Running both without them fighting

One Shot Fix corrects the whole focused field when you click its toolbar icon, and shows you the corrected text in a popup that you confirm with Apply. It does not underline as you type and does not replace Chrome's spell check. The two run independently.

1. 1

   Leave Chrome spell check on, Basic if the text is sensitive

   It costs nothing and catches typos at the moment you make them. Choose Basic when you type client data, credentials or anything under NDA.

2. 2

   Add the recurring proper nouns to Chrome's dictionary

   Right-click a flagged name or product and add it. Do this for the five or ten tokens that appear in almost everything you write, and the underline noise drops sharply.

3. 3

   Write the whole message first

   Do not correct as you go. A grammar pass on a finished thought produces a better result than one on a half-written sentence.

4. 4

   Copy the original text somewhere

   Select all in the field and copy it into a scratch note before you correct. There is no undo after Apply.

5. 5

   Click the One Shot Fix toolbar icon

   Pin it first if it is not visible: the puzzle-piece menu in Chrome and Edge, or Customize Toolbar in Firefox. The extension is invoked by a toolbar click; it does not add a keyboard shortcut and does not insert itself into Chrome's right-click spelling menu.

6. 6

   Read the popup, then Apply

   Check the names, numbers, dates and identifiers survived. That is the step Chrome spell check would never have prompted you to take, because it never touched them.

Where this breaks down

Add the second layer

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