The words get used interchangeably, but they aren't the same thing. Knowing which tool does what will save you time — and stop you sending an email that's technically correct but reads like a robot wrote it.
Spellchecker
Flags misspelled words against a dictionary. Fast, but blind to context — 'form the team' passes even when you meant 'from the team'. Every writing app in the world ships with one, and every writer has been let down by one.
I need a volunteer form from each team to attend the meeting on Tueday Tuesday.
Spellcheck catches 'Tueday'. It waves 'form' straight through — because 'form' is a real word. That's the whole limitation in one sentence.
Grammar checker
Applies rules to catch tense mismatches, subject–verb disagreement, misplaced modifiers. Better than spellcheck, but tends to nag about rules that don't apply to your writing style. If you write casually, most grammar checkers will spend the day highlighting your sentence fragments and contractions — both of which are fine, in context.
A grammar checker also can't tell whether your paragraph makes sense. It can tell you your comma is missing; it can't tell you the sentence is meandering.
AI proofreader
A proofreader reads the whole piece the way a human editor would: catches spelling and grammar, but also punctuation, formatting, consistency, and awkward phrasing. It suggests a corrected version rather than just flagging problems. When it does flag something, it explains why — so you actually learn.
A spellchecker asks 'is this word in the dictionary?' A proofreader asks 'does this sentence say what you meant?'
The other difference is that a proofreader will happily reword something for you if you ask. Here's a bureaucratic sentence rewritten in one click:
Please be advised that we are currently unable to process your request at this point in time.
We can't process your request right now — sorry about that.
When to use which
- Quick chat reply → spellcheck is fine.
- Work email or LinkedIn post → grammar checker or AI proofreader.
- Blog post, cover letter, essay, client work → AI proofreader every time.
- Anything that will be read by more than three people → AI proofreader, no exceptions.
The hidden third category: style
None of the three tools above will tell you your opening paragraph is boring. That's a style edit, and it's still your job. What a good AI proofreader will do is give you back a version of your text where the mechanics are out of the way — so you can focus on style without getting distracted by typos.
Where Verbao fits
Verbao is a full AI proofreader: spelling, grammar, punctuation, formatting and light style — with a corrected version you can copy in one click. Free up to 500 words, and it never changes your voice unless you ask. If you want to rework a sentence, the paraphraser is one button away. If you want to check just a comma, that's fine too — small pastes are the point.
One tool for spelling, grammar, and 'does this actually read well?' — that's the trade you're making when you move up from spellcheck to a proofreader.