Formal vs. Informal Register in Writing

The difference between formal vs. informal register in writing is a key concept that writers must learn. Here’s what you need to know.

In the English language, the level of formality in a piece of writing is known as its “register.” Though some writing can have a neutral register, the formal register and the informal register are far more common. 

Getting the register right is vital to giving the reader what they want. If you’re writing a blog post, you’ll use informal language, colloquialisms, and abbreviations often. If you’re writing an academic research report, you will use formal language, complex sentence structures, and a different word choice.

Being able to differentiate between the different registers is an important writing skill. It ensures your use of language is appropriate to the task at hand.

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What Is Register, and Why Does It Matter?

Formal vs informal register in writing

Different situations call for a different level of writing. Academic writing, for example, is more formal than a friendly letter.

I would guess that your grandma would not want to receive a letter from you filled with scientific data unless of course, she is a research scientist. Similarly, your professor would not want a paper with a lot of contractions and first-person descriptions in it, either. 

If you headed to a courtroom and watched the lawyer read a statement full of slang and informal speech, you would be confused. Similarly, if you were at a wedding and the best man was toasting the bride and groom with a highly formal, business-style speech, you would feel a disconnect.

When the level of formality, or the register, of a piece of writing, is correct, the writing feels good to the reader.

When it is not, the reader is confused and may not trust what you’re saying.

What Is a Formal Register?

The formal register is for formal publications and follows grammar rules carefully. This type of register avoids slang or colloquial terms, never ends a sentence with a preposition, and refrains from using contractions.

The formal register typically uses longer paragraphs of at least three to five sentences, sometimes more. It may have more complex sentences. It does not necessarily have a complex vocabulary, but it does have vocabulary appropriate to the topic.

Formal register uses primarily the third person point of view, though sometimes second-person is appropriate. It also spells out numbers less than 100. It uses active, not passive voice, and does not use words like because, so, but, also or like to start sentences. Sometimes writers call this the consultative register.

What Are Some Uses of Formal Register

Formal vs. Informal register
Essays use the formal register

You will use the formal register for situations like:

  • Research papers
  • Technical papers
  • Professional and business writing
  • Letters or emails in a professional setting
  • Essays
  • Other types of reports and academic and formal writing

Examples of Formal Register

Formal register is best seen in large pieces of writing, but these sentences have a formal tone to them that could qualify as formal register. 

  • Dear sir, The CEO would like to request a meeting to discuss the terms of the contract.
  • When the researcher heated the mixture, it combusted. 
  • Choice of words and verbs in a sentence has a direct impact on the register.

Formal register often shows up on the terms and conditions page of a website. Consider this one from the retailer

“Please read the following Terms & Conditions carefully as they affect your legal rights. These Terms & Conditions contain an arbitration agreement that requires the use of arbitration on an individual basis to resolve disputes rather than jury or any other court proceedings, or class actions of any kind.”

What Is Informal Register?

The informal register is a less structured, somewhat more conversational register. This register uses contractions, slang, colloquialism, and abbreviations often.

In informal writing, you will also see plenty of use of symbols, idioms, and figurative language. Incomplete sentences may show up, and short, punchy paragraphs are common.

First-person and second-person points of view are also possible with this register. The writer may even use extra punctuation to make a point. Sometimes writers call this the casual register.

What Are Some Uses of Informal Register?

The informal register is used for:

  • Blogging
  • Personal letters and email
  • Texting
  • Notes
  • Diaries
  • Journals
  • Storytelling
  • Social media

Examples of Informal Register

The informal register is pretty easy to spot. Some examples include:

  • We can’t go to the store right now.
  • Hi Nancy!!!!!!! How are you?
  • Have you heard what we’re doing this weekend?
  • I’m gonna tell you my idea because it’s awesome!

Sometimes, an informal register makes sense because of the target reader, rather than the situation. For example, this terms of service page from The Writers’ HQ uses the informal register, yet it covers a pretty formal topic.

“Hello! It looks like you’re hanging out on our website, and possibly even doing some retreats or courses or other things we offer. (We = Writers’ HQ. That’s us. Hi ????).

First things first: by using our site you’re agreeing to these T&C. If you don’t like them, you can opt-out by pressing the tiny little X at the top of your browser. Bye bye.”

Similarities and Differences Between Formal and Informal Register

Formal register and informal register in writing have very little in common. While both will have some reliance on grammar rules, the structure and professionalism of formal register look very different from the casual nature of informal.

The differences all come down to word choice. Formal words that are not conversational would be formal register, while the language you’d use when talking to your friends would be informal.

As you start paying attention to register, you’ll realize that you already use both formal and informal in your daily writing or speaking. Still, learning to use language register well in your writing will help you reach your target audience more effectively. 

Other Registers

In addition to formal and informal, you may find yourself using one of these registers:

  • Neutral Register: Neutral is the register that is used often for transactions. It allows first and second person, but does not get as casual as informal.
  • High Formal: For particularly professional documents, like legal papers or government writing, this is the register chosen. It uses formal vocabulary and complex sentence structure throughout.
  • Frozen Register: Also known as the static register, this register applies to language that has not changed due to custom or etiquette, such as religious quotes.
  • Intimate Register: The intimate register uses highly informal language and is often shared between close friends. 

The Final Word: Formal Register vs. Informal Register

Knowing when to use formal register vs. informal register is key to making your writing stand out. For business and academic papers, lean on the formal register, while for less formal work, informal will do nicely. Learn to distinguish these two as you work to make your writing appropriate for its audience.


  • Bryan Collins is the owner of Become a Writer Today. He's an author from Ireland who helps writers build authority and earn a living from their creative work. He's also a former Forbes columnist and his work has appeared in publications like Lifehacker and Fast Company.