7 Common Grammar Mistakes in Business Emails (With Fixes)
A single grammar slip in a client email can cost you credibility. Here are the 7 mistakes I see most often — and exactly how to fix each one.
Quick stat: A Grammarly-Harris poll found that 59% of respondents would question a company's professionalism based on grammar errors in their communication. In other words: your grammar is your first impression.
Why Business Email Grammar Actually Matters
Nobody expects you to write like a Pulitzer winner in a Tuesday-morning follow-up email. But consistent grammar mistakes send an unintentional message: rushed, careless, or — worse — underqualified. A hiring manager scanning your thank-you note or a client evaluating your proposal is not consciously grading your grammar. They are forming an impression, and sloppy writing undercuts everything else you bring to the table.
Below are the seven errors that show up in business inboxes every single day, each with a before-and-after fix you can apply immediately.
1. Your vs. You're
Why it happens: They sound identical. Autocorrect does not help because both are valid words.
The rule: "Your" shows possession. "You're" is a contraction of "you are."
Wrong
Correct
Self-check: Replace with "you are." If it fits, use "you're." If not, use "your."
2. Its vs. It's
Why it happens: Apostrophes usually signal possession — but "it's" breaks that pattern. This is the single most counterintuitive rule in English punctuation.
The rule: "It's" always means "it is" or "it has." "Its" shows possession, no apostrophe.
Wrong
Correct
3. Subject-Verb Agreement
Why it happens: Long sentences create distance between the subject and verb. By the time you reach the verb, you have forgotten whether the subject was singular or plural.
The rule: A singular subject takes a singular verb. A plural subject takes a plural verb. Ignore the words in between.
Wrong
Correct
Trick: Strip the sentence to its core. "The list ... is." Not "the list ... are." The prepositional phrase "of action items" is a distraction.
4. Comma Splices (Run-On Sentences)
Why it happens: You have two complete thoughts and try to join them with just a comma. It feels natural, but it is grammatically incorrect.
The rule: Do not join two independent clauses with only a comma. Use a period, semicolon, or a comma + coordinating conjunction (and, but, or, nor, for, so, yet).
Wrong
Correct
5. Passive Voice Overuse
Why it happens: Passive voice feels polite and diplomatic — which is exactly why it creeps into business writing. A little is fine. Too much makes you sound evasive.
The rule: In active voice, the subject performs the action. In passive voice, the subject receives the action. Prefer active.
Weak (Passive)
Strong (Active)
Active voice is shorter, clearer, and sounds more accountable.
6. Overly Long Sentences
Why it happens: You try to pack too much into one sentence — background, context, request, and justification all strung together with commas and "and."
The rule: If a sentence runs past 25-30 words, break it up. One thought per sentence is a good default for email.
Too Long
Fixed
7. Missing Parallel Structure
Why it happens: You list items in different grammatical forms without noticing. It reads awkwardly but can be hard to self-diagnose.
The rule: Items in a list or series must share the same grammatical form — all nouns, all -ing verbs, all infinitives, etc.
Wrong
Correct
A Clean Business Email Template
Here is a short follow-up email that avoids all seven mistakes. Use it as a sanity-check reference for your own writing.
Subject: Following Up on Tuesday's Demo
Hi Sarah,
Thanks for walking us through the platform on Tuesday. Your team's approach to data migration is solid, and we are excited about the potential fit.
I have two quick follow-up questions:
- Can you share the pricing breakdown for the Enterprise tier? We would need licenses for roughly 120 users.
- What does the typical onboarding timeline look like? Our Q3 planning wraps up next Friday, so I would love to slot this in before then.
Looking forward to hearing from you. Happy to jump on a call if that is easier.
Best,
James
Notice what this email does: short sentences, active voice, no comma splices, parallel questions, correct your/you're and its/it's throughout. It is professional without being stiff.
Run a Final Check Before Sending
You can catch most of these errors by reading your email out loud once before hitting send. Your ear will flag awkward phrasing that your eyes skim past. But for anything client-facing — proposals, pitch emails, executive summaries — a second pair of eyes (or an AI grammar checker) makes the difference between "good enough" and polished.
One Click Before You Hit Send
Paste your draft into our grammar checker. It flags all 7 mistake types above, plus tone issues, readability problems, and wordiness. Free, no account needed.
Check Your Email FreeFrequently Asked Questions
Should I use "Dear" or "Hi" in a business email?
In 2026, "Hi [Name]" is the standard for most professional email. Use "Dear" for very formal situations — legal correspondence, cold outreach to senior executives you have never met, or formal complaint letters. For everyday business communication, "Hi" is perfectly professional and avoids sounding stiff.
Is it unprofessional to use contractions in business emails?
No. Contractions like "you're," "it's," and "we're" make your writing sound natural and conversational. Avoiding them entirely ("you are," "it is," "we are") can come across as robotic. The key is using them correctly — which brings us back to Mistake #1 and #2 above.
How long should a business email be?
Aim for 5 sentences or fewer when possible. If you need more, use bullet points and short paragraphs. Nobody reads wall-of-text emails. If the topic is complex, consider whether a quick call would be more efficient.
Can AI grammar checkers handle business-specific language?
Modern AI checkers understand context, including industry jargon and formal tone. They are better than basic spell checkers at catching the type of errors listed in this article because they analyze the sentence structure, not just individual words.