Quick Answer: Nine of the most common business writing mistakes involve grammar and word choice errors that undermine professional credibility: confusing “fewer” and “less,” misusing “it’s” and “its,” incorrect “neither/nor” construction, mixing up “then” and “than,” sentence-ending prepositions, subject-verb disagreement, “lie” vs. “lay,” misplaced modifiers, and irregular verb and noun forms. Fixing these makes business writing cleaner, clearer, and more credible.
Grammar is finicky, and some of the rules just don’t make straightforward sense. (Remember the rule about not splitting infinitives? That was passed down from Latin, where you literally couldn’t split an infinitive, as infinitives were single words.) Even so, proper grammar is a hallmark of professional writing, just as proper formatting is.
These nine common business writing mistakes appear across industries and experience levels. Most are easy to fix once you know what to look for. To help you avoid common pitfalls, we’ve prepared a list of nine common business writing mistakes in business writing:
1. Confusing “Fewer” and “Less”
“Fewer” is used with nouns you can count (“one meeting, two meetings”), and “less” applies to uncountable nouns (you can’t say “one effort, two efforts”). You can have fewer meetings with less effort.
This distinction matters in business writing because using the wrong word reads as careless, even if the meaning is clear. A quick test: if you can count it, use “fewer.” If you can’t, use “less.”
2. Mixing Up “It’s” and “Its”
This is an exception to the apostrophe rule for forming possessives. “Its” is the possessive form. “It’s” is a contraction of “it is.” The apostrophe here signals omission, not ownership.
In professional documents, this error stands out to readers. When in doubt, read the sentence aloud with “it is” in place of the word. If it doesn’t make sense, you want “its.”
3. Misusing “Neither/Nor” in Business Writing
“Nor” exists specifically for this paired construction. It is not a synonym for “or.” When using “neither,” the following clause must use “nor,” not “or.”
Correct: “Neither the report nor the proposal was submitted on time.”
Incorrect: “Neither the report or the proposal was submitted on time.”
This mistake is common in business emails and reports, where writers default to “or” out of habit.
4. Confusing “Then” and “Than”
“Then” refers to time or sequence. “Than” is used for comparisons. They sound similar but serve entirely different purposes, and mixing them up disrupts the logic of a sentence.
Correct: “Review the data, then write the summary.”
Correct: “The revised draft is clearer than the original.”
Because business writing frequently involves both time-based sequences and comparative analysis, this distinction comes up often. Getting it right keeps your documents precise.
5. Ending Sentences With Prepositions
As a general rule, avoid ending sentences with prepositions like “by,” “over,” “with,” or “around.” In formal business writing, this can read as unpolished.
That said, there are exceptions. Some fixed phrases (“put up with,” “follow up on”) end with a preposition naturally, and forcing an alternative construction can sound awkward. Use judgment based on formality and context.
6. Breaking Subject-Verb Agreement Rules
Subject-verb agreement means using plural verbs for plural subjects and singular verbs for singular subjects. Errors here are more common than they seem, especially in longer sentences where the subject and verb are separated by a clause.
Incorrect: “The team of analysts were reviewing the report.”
Correct: “The team of analysts was reviewing the report.”
(“Team” is the subject, not “analysts.” “Team” is singular.)
In business writing, subject-verb disagreement can make a sentence feel off even when readers can’t identify exactly why.
7. Mixing Up “Lie” and “Lay”
“Lay” requires an object. You lay something down. “Lie” does not take an object. You lie down.
This distinction trips up most writers because the past tense of “lie” is “lay,” which creates additional confusion.
Present: “I need to lie down.” / “Please lay the documents on the table.”
Past: “He lay down after the meeting.” / “She laid the documents on the table.”
In professional writing, the clearest fix is to restructure the sentence when you are unsure.
8. Using Misplaced Modifiers in Professional Writing
Modifiers should be placed as close as possible to the word or phrase they describe. When they are not, the sentence becomes confusing or unintentionally absurd.
Incorrect: “Having been in operation for ten years, the client trusted our team.”
Correct: “Our team, which had been in operation for ten years, earned the client’s trust.”
Misplaced modifiers are especially common in business reports and proposals, where writers are working quickly. A careful re-read of each sentence from the reader’s perspective catches most of these.
9. Irregular Verbs and Nouns: The Oddball Business Writing Mistakes
English has a significant number of irregular verbs and nouns that do not follow standard pluralization or conjugation rules. These are simply exceptions that need to be learned.
Common irregular verb errors in business writing include “brought” (not “bringed”), “arose” (not “arised”), and “led” (not “leaded”). Common irregular noun errors include “criteria” (plural of “criterion”) and “data” (plural of “datum”), both of which are often treated as singular in professional documents.
When unsure, a style guide or dictionary is the most reliable reference.
Why These Mistakes Keep Appearing
Grammar errors in business writing are not usually signs of carelessness. They reflect the fact that most professionals write quickly, under deadline, without a formal editing process. Many of the rules above were never explicitly taught.
The best way to reduce these errors is to build a personal editing checklist based on your own patterns, slow down during revision, and read documents aloud before sending. Reading aloud forces you to process each word individually, which catches errors that silent reading skips over.
For teams, establishing shared writing standards and a consistent review process reduces errors across all contributors, not just individual writers.
Grammar Is Part of Business Writing Credibility
In professional environments, grammar signals attention to detail. A proposal, report, or client communication that contains consistent errors can undermine confidence in the content itself, even when the underlying analysis is strong.
That said, grammar is only one dimension of strong business writing. Structure, clarity, and strategic organization have an equal or greater impact on whether a document achieves its goal. The most effective approach treats grammar correction and writing strategy as complementary skills, both worth developing.
To learn more about improving business writing across your team, contact Hurley Write.
Some verbs have irregular past tenses; some nouns have irregular plurals. The best solution is to learn these oddities.
Frequently Asked Questions
What are the most common grammar mistakes in business writing?
The most frequent grammar mistakes in business writing include confusing “fewer” with “less,” misusing “it’s” and “its,” subject-verb disagreement, and misplaced modifiers. These errors are easy to overlook but consistently undermine professional credibility. Most can be avoided by slowing down during revision and reviewing documents with a grammar-focused checklist.
Why does grammar matter in professional business writing?
Grammar signals attention to detail and professional competence. When business documents contain grammatical errors, readers may question the writer’s credibility or lose confidence in the information itself. In client-facing documents, proposals, and reports, even minor grammar mistakes can affect how the reader perceives the organization’s overall professionalism and reliability.
How do I stop making the same grammar mistakes repeatedly?
The most effective approach is to build a personal editing checklist based on the mistakes you make most often. Reviewing your own writing with a list of known problem areas catches errors faster than re-reading for general correctness. Structured business writing training also helps by making correct usage second nature through deliberate practice and feedback.
Is grammar the most important aspect of business writing?
Grammar matters, but it is not the highest priority. Structure, clarity, and purpose have a bigger impact on whether a business document achieves its goal. A grammatically perfect document that buries its key point or ignores the reader’s needs will still fail. Strong business writing requires both grammatical correctness and strategic communication skills.
Can business writing training help with grammar and word choice errors?
Yes. Writing training addresses both grammatical precision and broader communication strategy. Participants learn to catch common word choice errors, improve sentence construction, and apply consistent standards across documents. Teams that train together also develop shared language and expectations, which reduces errors that stem from inconsistent usage across contributors.
