Practical Computer Advice
from Martin Kadansky
Volume 12 Issue 11
November 2018
Capitalization Confusion: When Does It Matter If You Type UPPERCASE Letters vs. lowercase?

The problem

In regular English, there are a number of words whose first letters should be capitalized, including proper nouns ("Abraham Lincoln"), the start of a sentence ("It was the best of times..."), the title and name of a specific officeholder ("Mayor Smith"), and many others, as well as words whose meanings change completely when capitalized, like "reading" (a book) vs. "Reading" (the town or the railroad company), "march" (to walk) vs. "March" (the month or the surname), "bill" (an invoice, the visor on a cap, a duck's beak, a piece of paper money, a proposed law, etc.) vs. "Bill" (the name).

Similarly, when using technology, sometimes typing lowercase letters vs. capitals doesn't change how things work, but other times it can make the difference between success and failure.

When capitalization doesn't matter

Here are some common situations when capitalization doesn't matter:
  • Simple web addresses (URLs) that only use the base part (domain name): Typing "" will work just as well as "wWw.aMaZoN.cOm"
  • Email addresses: "" is equivalent to "MARTIN@KADANSKY.COM" and "Martin@KaDanSky.Com"
  • Google search keywords: Searching for "electric golf cart" is the same as searching for "Electric Golf Cart" or "ELECTRIC GOLF CART"
  • Names of documents and folders: Your computer considers the names "abc" and "ABC" to be equivalent
When capitalization does matter

Here are some situations when capitalization matters, plus the consequences of mistyping:
  • Longer web addresses, with multiple components separated by forward slashes: "" (correct) and "" (incorrect) are different addresses; in the worst case you'll either get an error or get redirected to the site's home page, but either way you won't get the web page that you wanted; technically the details depends on the company that's hosting the web site
  • Passwords: Capitalization almost always matters, i.e., "abc123" and "ABC123" are different passwords; in the worst case you'll fail to sign in to the account, which may also trigger a security alert, and if you try too many times your account may get locked
  • More complex Google searches where you don't properly capitalize special keywords like "OR": A search for "x OR y" (which combines a search for "x" with a search for "y") will get different results than "x or y" (which searches for those 3 words); if you confuse these, you won't get the search results you wanted
Thus, especially when writing down passwords, it's very important to carefully distinguish uppercase letters from lowercase, as well as the digit 5 (five) from the letter "S" (as in Sam), the digit 0 (zero) from the letter "O" (as in Oscar), and the digit 1 (one) from the lowercase letter "l" (as in little) from the vertical bar (|).

When capitalization might matter

There are some other rare technical situations when capitalization might make a difference, for example:

Sorting text: It's not likely, and common programs like Microsoft Word and Excel don't have this problem, but if you sort a list of words like "apple, Banana, carrot," depending on the software that you're using, you might get "Banana, apple, carrot" if the software treats uppercase and lowercase text as different instead of equivalent. A capitalized word like "Banana" sorting before a lowercase word like "apple" would most likely be caused by an old-school, literal computer approach, where the letters "A-Z" come before "a-z" because in the ASCII code (American Standard Code for Information Interchange, developed in the 1960s), the numeric values assigned to capital letters (65-90) are lower than those assigned to lowercase (97-122).


Apart from situations where capitalization makes a technical difference, in other areas of electronic communication (including email subject and body, instant messaging, text messaging, etc.), the use of ALL CAPS is considered to be extreme emphasis or "shouting," so it should be used sparingly. On the other hand, some visually impaired users type their messages in all-caps so they can read and edit them more easily, so unless you already know the other person, I recommend being patient and asking why they're using all-caps, rather than assuming that they're intentionally shouting.

Here's a reasonable alternative that expresses medium emphasis, and it's useful especially when bold or italic are not convenient or available: Use asterisks or underscores to surround the lowercase word you're emphasizing, e.g., "That's *exactly* what I wanted!" or "You _can't_ be serious!"

Mixing Capital letters and lowercase

There are other common techniques that you can use to make compound names more readable by mixing upper- and lowercase letters, especially when inserting spaces is not permitted, and using underscores (_) is clumsy or unnecessarily lengthy.

For example, to make the web address more readable and easier to type, you could:
  • Use "Pascal Case":, capitalizing the first letter of every word in the name portion; the term comes from the style popularized by common naming conventions that evolved with the Pascal programming language
  • Use "Camel Case":, which is like Pascal Case, but with the first letter as lowercase; the term comes from the capital letters resembling the humps on a camel
"InterCaps" (an abbreviation of "Internal Capitalization") is a more general term that refers to techniques like these.

Where to go from here
How to contact me:
phone: (617) 484-6657

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I love helping people learn how to use their computers better! Like a "computer driving instructor," I work 1-on-1 with small business owners and individuals to help them find a more productive and successful relationship with their computers and other high-tech gadgets.

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