Formal vs. Informal Language in Academic Writing

The line between formal and informal language is one of the first things that marks a piece of writing as academic or not. Academic writing uses a formal register: it avoids contractions, slang, casual qualifiers, and conversational phrasing, in favor of precise, measured language. Getting this register right is harder than it sounds, because formality is not a single switch. It runs on a spectrum, and writers fail at both ends, some too casual for the context, some so stiff that the prose becomes unreadable. This guide maps the markers of informal language, shows how to convert each to its formal equivalent, and explains where the line actually falls.

Quick answer

Formal academic language avoids contractions (use "do not," not "don't"), slang and colloquialisms, casual qualifiers ("really," "a lot," "kind of"), conversational openers ("Well," "So"), cliches, and direct address to the reader. It favors precise word choice, complete constructions, and a measured tone. The goal is not stiffness: writing can be formal and still clear and readable. The most reliable way to fix register is a dedicated pass that reads only for informal markers, since casual phrasing slips in during drafting and is easy to miss while focused on ideas. Formality should serve clarity, never replace it.

Why Register Matters in Academic Writing

Register is the level of formality a piece of writing adopts for its audience and purpose. A text message to a friend, a cover letter, and a journal article all use different registers, and each is correct in its context. Academic writing calls for a formal register because its audience, professors, examiners, and peer reviewers, expects it, and because formality supports the precision and objectivity that scholarly argument depends on.

The cost of getting register wrong is that it distracts the reader from the argument. A reviewer who hits a contraction or a piece of slang in an otherwise serious paper is pulled out of the content for a moment, and a paper that does this repeatedly reads as careless or unpolished. Formality is part of how academic writing earns trust: it signals that the writer knows the conventions of the field and has taken the work seriously. This is one element of the broader academic voice that scholarly writing requires.

Register is also not the same as difficulty. Formal does not mean hard to read, and informal does not mean clear. The aim is a register that is formal enough for the context while staying as clear as possible. That balance, formal but clear, is the target this guide works toward.

The Markers of Informal Language

Informal language shows up in a handful of predictable forms. Learning to recognize them is most of the work, because once you can see them, converting them to a formal equivalent is usually straightforward.

Contractions

Contractions are the most common informal marker in student writing. "Do not" becomes "don't," "it is" becomes "it's," "cannot" becomes "can't." Most academic style guides call for the full form in formal writing. The fix is mechanical: expand every contraction. This is one of the easiest informal markers to catch with a dedicated search, and doing so in a final pass removes a large share of the casual feel from a draft.

Slang and colloquialisms

Slang and colloquial expressions are everyday spoken phrases that read as casual on the page: "a big deal," "tons of," "stuff," "get across," "deal with." These are clear in conversation but signal informality in academic prose. The fix is to replace them with precise alternatives. "Tons of data" becomes "extensive data" or, better, a specific quantity. "Deal with the problem" becomes "address the problem." The replacement is usually both more formal and more precise.

Casual qualifiers and intensifiers

Words like "really," "very," "so," "a lot," "kind of," "sort of," and "pretty much" are conversational hedges and intensifiers that weaken academic prose. "Really significant" is both informal and imprecise; "significant" alone is stronger, or a specific figure is stronger still. "Kind of suggests" undercuts the claim without qualifying it usefully. The fix is to cut the casual qualifier and either state the claim cleanly or replace the vague hedge with a precise one. Calibrating how strongly to state a claim is the subject of the cluster's hedging guide.

Conversational openers and fillers

Openers like "Well," "So," "Now," "Of course," and "Obviously," carried over from speech, signal informality at the start of a sentence. So do filler phrases like "at the end of the day" and "when all is said and done." These add no information and lower the register. The fix is simply to delete them; the sentence almost always reads better without the conversational throat-clearing.

Cliches and figures of speech

Cliches such as "think outside the box," "the bottom line," "a double-edged sword," and "read between the lines" are informal and imprecise. They substitute a familiar phrase for a specific thought. The fix is to say what you actually mean in precise terms. "A double-edged sword" becomes a clear statement of the specific benefit and the specific cost. The precise version is always more informative than the cliche.

Direct address to the reader

Addressing the reader as "you" is conversational and generally avoided in academic writing. "You can see that the data support this" becomes "the data support this." Second-person address assumes a casual relationship with the reader that the academic register does not adopt. The fix is to recast the sentence so it describes the evidence or the argument rather than instructing the reader. The handling of the first person, "I" and "we," is a separate question with its own disciplinary conventions, covered in the cluster's first-person pronouns guide.

Informal to Formal: Worked Examples

Seeing the conversion in whole sentences makes the pattern concrete. In each pair, the informal version is not wrong in conversation; it is simply the wrong register for academic writing, and the formal version is both more appropriate and usually more precise.

Informal: "The results were really surprising and showed that the old theory doesn't hold up."
Formal: "The results were unexpected and indicate that the established theory does not hold."
Informal: "We looked at a ton of studies, and basically they all say the same thing."
Formal: "The review examined 43 studies, which reported consistent findings."
Informal: "At the end of the day, this approach is kind of a game-changer for the field."
Formal: "This approach represents a substantial advance for the field."
Informal: "So, it's pretty clear that more research needs to be done here."
Formal: "Further research is needed in this area."

Notice that the formal versions are not longer or more complicated. In most cases they are shorter, because removing casual qualifiers and cliches cuts words that were doing no work. This is the key point about formality: it is compatible with concision and clarity, and it often improves both.

The Other Failure: Forced Formality

Writers who learn that academic writing is formal often overcorrect, producing prose so stiff and inflated that it becomes hard to read. This is the opposite failure, and it is just as damaging to academic voice as excessive informality. Forced formality usually takes a few forms.

The most common is inflated vocabulary: reaching for the longest available word in the belief that it sounds more scholarly. "Utilize" instead of "use," "in order to" instead of "to," "the methodology employed in the present investigation" instead of "the method." These do not raise the quality of the writing; they bury the meaning. A second form is heavy nominalization, turning verbs into nouns so that sentences lose their action: "the implementation of the modification was undertaken" instead of "the design was modified." A third is overloading sentences with subordinate clauses until the reader loses the thread.

The principle that resolves both failures is the same: formality serves clarity, never replaces it. Academic writing is formal because the formal register supports precise, credible communication, not because difficulty is a virtue. The strongest academic prose is formal and clear at once. When formality and clarity seem to conflict, clarity wins, because the entire purpose of the writing is to be understood.

How to Fix Register in Your Own Writing

Register problems are best fixed in a dedicated revision pass, separate from drafting. While composing, your attention is on ideas, and casual phrasing slips in unnoticed. A focused pass that reads only for register catches what drafting misses.

Search for contractions first. This is the fastest win. Use your word processor to find every apostrophe and expand the contractions. It takes minutes and removes a large share of the informal feel from a draft.
Scan for casual qualifiers. Read through specifically hunting for "really," "very," "so," "a lot," "kind of," and "pretty much." Cut them, and either state the claim cleanly or replace the vague hedge with a precise one.
Flag anything that sounds spoken. Read the draft aloud. Anything that sounds like conversation, an opener, a cliche, a casual phrase, is a register marker to revise. The ear catches informality the eye skates over.
Check the other direction too. While reading for register, watch for forced formality: inflated words, heavy nominalization, sentences buried in clauses. Replace "utilize" with "use," unpack nominalizations back into verbs, and split overloaded sentences. The target is formal and clear, not formal at any cost.

When Professional Editing Helps

Register is one of the hardest things to judge in your own writing, because your own casual phrasing reads as normal to you, and your own forced formality reads as appropriately scholarly. A professional academic editor hears both, the contraction that slipped through and the inflated sentence that buries its meaning, and calibrates the prose to the formal-but-clear register your field expects. This is exactly the kind of consistency work that is difficult to do on your own manuscript, because the familiar stops registering.

Editor World's academic editing and professional proofreading services adjust register throughout a document, removing informal markers and unpacking forced formality so the writing reads at the level reviewers expect. You choose your own editor by discipline and verified client ratings, and you can message any editor before submitting. Every document is edited entirely by a qualified native English editor, with no AI tools used at any stage. For specific document types, see our journal article editing and dissertation editing services. For the broader conventions of academic writing, see the do's and don'ts of academic writing.

Frequently Asked Questions

What is the difference between formal and informal language in academic writing?

Formal language is the register academic writing requires: it avoids contractions, slang, casual qualifiers, conversational openers, cliches, and direct address to the reader, favoring precise and measured wording instead. Informal language is the casual register of everyday speech, which is correct in conversation but signals a lack of seriousness in an academic context. The difference is not about difficulty, since formal writing can still be clear and informal writing can be unclear. It is about matching the register that professors, examiners, and peer reviewers expect. Formality supports the precision and objectivity that scholarly argument depends on, which is why academic writing adopts it.

Can I use contractions in academic writing?

Most academic style guides call for the full form rather than contractions in formal writing, so "do not" is preferred over "don't," "it is" over "it's," and "cannot" over "can't." Contractions are the most common informal marker in student writing, and expanding them is one of the easiest ways to raise the register of a draft. The fix is mechanical: search the document for apostrophes and expand each contraction in a final pass. Some less formal academic contexts, such as a reflective piece or certain blog-style assignments, may permit contractions, so check your assignment guidelines, but for formal papers, theses, and journal articles, the full form is the safe default.

What words should I avoid in academic writing?

Avoid casual qualifiers and intensifiers like "really," "very," "so," "a lot," "kind of," "sort of," and "pretty much," which weaken prose and add no precision. Avoid slang and colloquialisms such as "tons of," "stuff," "a big deal," and "deal with," replacing them with precise alternatives. Avoid conversational openers like "Well," "So," and "Obviously," along with filler phrases like "at the end of the day." Avoid cliches such as "think outside the box" and "a double-edged sword," which substitute a familiar phrase for a specific thought. In most cases the formal replacement is both more appropriate and more precise than the informal word it replaces.

Does formal academic writing have to be hard to read?

No. Formality and difficulty are not the same thing, and the strongest academic writing is formal and clear at once. A common mistake is overcorrecting into forced formality: reaching for inflated vocabulary like "utilize" instead of "use," loading sentences with heavy nominalizations that bury the action, and stacking subordinate clauses until the reader loses the thread. This stiff, inflated prose is just as damaging to academic voice as excessive informality. The principle that resolves both failures is that formality serves clarity rather than replacing it. Academic writing is formal because the formal register supports precise, credible communication, not because difficulty is a virtue. When formality and clarity seem to conflict, clarity wins.

How do I make my writing sound more formal?

Fix register in a dedicated revision pass separate from drafting, since casual phrasing slips in unnoticed while you are focused on ideas. Start by searching for contractions and expanding them, which is the fastest win. Next, scan specifically for casual qualifiers like "really," "very," and "kind of," and cut them or replace them with precise wording. Then read the draft aloud and flag anything that sounds spoken, including conversational openers and cliches. Finally, check the opposite direction for forced formality, replacing inflated words like "utilize" with "use" and unpacking heavy nominalizations back into verbs. The target throughout is a register that is formal and clear, not formal at any cost.

Is it wrong to address the reader as "you" in academic writing?

Direct second-person address is generally avoided in academic writing because it is conversational and assumes a casual relationship with the reader that the academic register does not adopt. A sentence like "You can see that the data support this" is better recast as "The data support this," which describes the evidence rather than instructing the reader. This is a register issue distinct from the question of first-person pronouns like "I" and "we," which varies by discipline and has its own conventions. Some instructional or reflective genres do use second person, so check the conventions of your assignment, but for formal academic papers, recasting away from direct address is the standard practice.

Are formal sentences longer than informal ones?

Not usually, and often the opposite. Converting informal language to formal language frequently makes a sentence shorter, because removing casual qualifiers, cliches, and filler phrases cuts words that were doing no work. For example, "At the end of the day, this approach is kind of a game-changer" becomes the shorter and more precise "This approach represents a substantial advance." Formality is compatible with concision, and the two often improve together. The belief that formal writing must be long and elaborate leads to forced formality, which buries meaning. The strongest formal academic prose uses the fewest words that convey the idea precisely.

Does the right level of formality depend on the discipline?

The core markers of informal language, contractions, slang, casual qualifiers, and cliches, are avoided across essentially all academic fields, so the foundation of formal register is consistent. What varies by discipline is the surrounding conventions: how much the passive voice is used, whether the first person is acceptable, how long and complex sentences tend to run, and how heavily writers hedge their claims. A philosophy paper and a chemistry paper are both formal, but they calibrate these elements differently. The most reliable way to judge the right level for your field is to read its published literature closely, since the conventions are learned by example rather than from a universal rulebook.

Reviewed by the Editor World editorial team. Editor World is a professional human-only editing and proofreading marketplace founded in 2010 by Patti Fisher, PhD, a graduate of The Ohio State University. The company serves academic researchers, doctoral candidates, faculty, graduate students, and business professionals worldwide, and has been BBB A+ accredited since 2010, with 5.0/5 Google Reviews and 5.0/5 Facebook Reviews. Editor World has edited more than 140 million words for over 8,000 clients in 65+ countries and is a multiple Gold and Bronze Stevie Award winner. Its native English editors come from the United States, the United Kingdom, and Canada, with subject-matter expertise across the social sciences, the natural and physical sciences, medicine, engineering, computer science, and the humanities. Fewer than 5% of applicants are accepted to the editor panel. Editor World is recommended by the Boston University Economics Department, University of San Diego, University of Michigan, UCLA, University of Missouri, and more. No AI tools are used at any stage.