Traditional spell checkers catch typos and obvious misspellings. AI grammar checkers go much further — they understand context and sentence structure, catching the kinds of errors that spellcheck misses entirely.
What an AI grammar checker catches
Spelling errors
Simple typos and misspellings:
- "recieve" → "receive"
- "seperate" → "separate"
- "definately" → "definitely"
Grammar errors
Structural problems in sentences:
Subject-verb agreement: "The data shows" vs "The data show" (data is plural in formal usage)
Tense consistency: Mixing past and present tense within the same passage
Pronoun agreement: "Everyone should bring their laptop" vs "Everyone should bring his laptop"
Dangling modifiers: "Walking down the street, the trees looked beautiful" (who was walking?)
Punctuation errors
- Missing or extra commas
- Incorrect apostrophe usage ("its" vs "it's")
- Run-on sentences that need splitting
- Comma splices (two independent clauses joined only by a comma)
Style issues (Deep Check mode)
- Overly complex sentences that reduce clarity
- Passive voice where active would be clearer
- Redundant phrases ("end result", "future plans", "completely eliminate")
- Weak word choices that could be more precise
Common grammar mistakes explained
Affect vs Effect
"Affect" is usually a verb ("The weather affects my mood"). "Effect" is usually a noun ("The effect was immediate").
Its vs It's
"Its" is possessive ("The dog wagged its tail"). "It's" is a contraction for "it is" or "it has" ("It's raining").
Your vs You're
"Your" is possessive ("Is this your book?"). "You're" is "you are" ("You're welcome").
Then vs Than
"Then" refers to time ("First do this, then do that"). "Than" makes comparisons ("Better than expected").
Who vs Whom
"Who" is a subject ("Who called?"). "Whom" is an object ("To whom did you speak?").
Tips for better writing
Read aloud before submitting
Your ear catches errors your eyes miss. If a sentence sounds awkward when spoken, it's probably awkward in writing.
One idea per sentence
Long sentences with multiple clauses are harder to read. Break complex thoughts into two shorter sentences.
Active voice as default
"The report was written by the team" → "The team wrote the report." Active voice is clearer and more direct.
Vary sentence length
All short sentences feel choppy. All long sentences feel exhausting. Mix lengths for rhythm.
Eliminate filler phrases
- "In order to" → "to"
- "Due to the fact that" → "because"
- "At this point in time" → "now"
- "The reason why is that" → "because"
When not to rely on grammar checkers
Grammar checkers are tools, not authorities. They make mistakes:
- Intentional stylistic choices: Sentence fragments for emphasis are correct in creative writing
- Technical language: Medical, legal, or scientific terminology may be flagged incorrectly
- Dialectal variations: American vs British English, formal vs informal registers
- Context-dependent correctness: "I could care less" vs "I couldn't care less" — both exist, meanings differ
Always review suggestions critically rather than accepting them automatically.
How to check grammar free
- Go to Grammar Checker
- Paste or type your text
- Choose Quick Check or Deep Check
- Click Check Grammar
- Review highlighted errors with explanations
- Copy the corrected text