Capital vs. lowercase letters

Learn the ins and outs of letters big and small.

Taylor Hartley

Taylor Hartley

Published January 8, 2024

Capital vs. lowercase letters

Learn the ins and outs of letters big and small.

Taylor Hartley
Author Taylor Hartley

Jan 8, 2024

Capital vs. lowercase letters

Learn the ins and outs of letters big and small.

Taylor Hartley

Taylor Hartley

Jan 8, 2024

Key takeaways

  • Letter case matters – Capital letters and lowercase letters serve different roles, and children need to know when and where to use each kind.
  • Uppercase signals importance – Typically, capital letters signal important parts of the sentence, whether that be the beginning of the sentence or specific people or places.
  • Lowercase is usually the way to go – Most writing uses lowercase letters. Unless you have a specific reason to use an uppercase letter, you should stick with lowercase.

Whether to use upper or lower case letters is one of the first things students will learn when discovering the ins and outs of English. But, even experienced English speakers and writers can get capitalisation rules mixed up. 

Like with most English grammar, there are unique situations that bend the rules and make something as simple as capitalisation a little tricky at times. Read on to learn all you need to know about when and where to capitalise.

Rules for capital letters

At the beginning of sentences

This is a simple rule that remains universally true. You must capitalise the first letter of a sentence, no matter what it is. Capitalising the first word makes the new sentence stand out on the page, aiding in readability and signaling the start of a new idea. 

This rule never changes, which makes it one of the easiest English grammar rules to remember. 

For proper nouns

Proper nouns are nouns (words that identify people, places, things, and ideas). They indicate specific individual things. 

For example, a common noun might be “person,” but “Hugh Grant” is a specific person, making his name a proper noun. Proper nouns include names of people and places and specific titles that function like names (like calling someone “Dad” as their name). 

Proper nouns are almost always capitalised unless the name specifically asks for a lowercase letter or other unconventional capitalisation choices. 

For acronyms and initialisms

Sometimes, longer names or phrases are reduced into acronyms to make them easier to remember or say. You make an acronym by taking the first letter of every word in a name or phrase and contributing it to the acronym. 

For instance, the National Aeronautics and Space Administration uses the acronym NASA. 

Typically, each letter that makes up an acronym will be capitalised. But, some acronyms slip in a lowercase letter or two to make the acronym into a more familiar word. 

Note that words like “and,” “of,” and “in” usually do not get a letter as part of an acronym. Conjunctions (and, but, etc.), prepositions (in, of, etc.), and articles (the, a, etc.) are seldom included in acronyms. 

Using capital letters in writing

In headings and titles

The rule of thumb for titles is that you capitalise all words except for conjunctions, prepositions, and articles. You also capitalise the first word of the title regardless of its part of speech. 

For example, the classic Faulkner novel The Sound and the Fury capitalises the first “the” because it is at the start of the title. But, the second “the” remains lowercase. 

For emphasis

At times, you may make every letter in a word all caps to add some dramatic emphasis to whatever you are saying. For instance, you might write that people should NEVER antagonise a tiger to emphasise its importance. 

With that in mind, you should also note that this is considered rather informal. You should avoid this kind of emphasis in more formal communications or with people you are unfamiliar with. The all caps can come across as hostile, hence why you should save it for more casual settings. 

If you do use capital letters for emphasis, capitalise every letter so the choice looks intentional and not like a typo.

Rules for lowercase letters

In sentences

Letters in sentences are lowercase unless they are capitalised for a specific reason. You can consider lowercase to be the default option for letters, and uppercase is only for special circumstances. 

For common nouns

Sometimes, there is confusion between letter cases and nouns. You need to distinguish between proper and common nouns when determining if you need upper or lowercase letters. 

Any noun that names a non-specific person, place, thing, or idea is a common noun, and you do not capitalise it. 

For example, “horse” is a common noun because the word is not naming a specific horse. If the horse’s name was “Jerry,” the name “Jerry” would, of course, be capitalised because it is a proper noun.

For non-initial words in titles

When writing out titles, any articles, prepositions, and conjunctions that do not come at the beginning of the title will be lowercase. 

For example, The Taming of the Shrew uses lowercase for “of” and “the” because “of” is a preposition and “the” is an article. The first “the” is capitalised, though, because it comes at the start of the title.

Using lowercase letters in writing

In informal writing

Some people choose to forgo capitalising things like proper nouns or the beginnings of sentences. This is informal and can lead to some confusion since some common nouns can also function as names. 

However, the lowercase approach can make your writing seem much more casual and relaxed. Some readers interpret capital letters as aggressive. The prevalence of auto-capitalisation with some apps also might explain why some writers fail to capitalise the first word of a sentence — they are used to having it done for them.

In emails and texts

In emails, you generally want to conduct yourself formally, which means paying close attention to proper capitalisation. Texting can be much more informal, which leads people to omit capitalisation. 

You’ll also see people use lowercase letters to substitute longer words like “u” for “you,” and these are often lowercase.

Comparing capital and lowercase letters

Role in reading comprehension

It may seem like a bother at first to concern yourself with what to capitalise. But, these rules help dramatically with reading comprehension. For one, some words can be common nouns, verbs, or proper nouns depending on the context. 

For instance, “polish” with a lowercase “p” is a verb meaning to make something shiny and smooth, but if you capitalise it, you get “Polish,” a word for people and things from Poland. 

Whether a letter is capitalised can change its meaning, so pay close attention to the letter case. 

Impact on visual presentation

Capital letters also aid in the visual presentation and appeal of writing. For one, the capital letter at the start of a new sentence makes the breakdown of new ideas much easier to recognize. 

Proper nouns and words emphasized with uppercase letters also stand out more in long paragraphs. They draw the reader’s attention and emphasize the word more.

Common mistakes with capital and lowercase letters

While less complex than other English language rules, capitalisation can still be a little tricky if you don’t watch out for these common issues. 

  • Overuse of capital letters. Some people will capitalise words at random, either through typos or because they think the uppercase letters are necessary. When you go to capitalise a word, make sure you have a specific reason for doing so. 
  • Forgetting to switch to lowercase letters. When typing in all caps for emphasis, some might forget to toggle the caps lock, resulting in an email that sounds like screaming. A wayward pinkie finger may also accidentally toggle caps. 
  • Incorrect capitalisation in titles and headings. Titles are one of the trickiest parts of capitalisation. At a glance, what gets capitalised and what doesn’t might seem erratic. 


In short, you should watch how you capitalise letters because it can make a huge impact on how your writing looks and even what it means. With careful attention to a handful of rules, though, you’ll have no trouble with letter case.

Explore capital and lowercase letters with DoodleEnglish

DoodleEnglish is an app that’s filled with thousands of fun, interactive exercises covering grammar, punctuation, spelling and more!

Designed by teachers, it creates each child a unique work programme tailored to their needs, boosting their confidence and skills in English. Try it for free today!

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FAQs about capital vs. lowercase letters

Capitalise letters at the start of sentences and titles, when writing out proper nouns, when writing acronyms, and for all words other than articles, conjunctions, and prepositions in titles.   

Generally, every letter that corresponds with a word in an acronym gets a capital letter except for articles, conjunctions, and prepositions. Sometimes, though, some acronyms use lowercase letters or grant an acronym letter to a part of speech that’s not normally represented to make the acronym spell out a specific word.

Capitalising words randomly in the middle of the sentence is incorrect. Another incorrect use is capitalising the first letter in a word when you are going for emphasis. 

Screenshot 2023-10-13 at 16.29.14

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