Updated: 08/16/2021 by Computer Hope
Underscore before and after a word.

Alternatively referred to as a low line, low dash, and understrike, the underscore ( _ ) is a symbol found on the same keyboard key as the hyphen. The picture shows an example of an underscore at the beginning and end of the word "Underscore."

Where is the underscore key on the keyboard?

Below is an overview of a computer keyboard with the underscore key highlighted in blue.

Underscore key

How to create the "_" symbol

Creating the "_" symbol on a U.S. keyboard

To create the underscore using a U.S. keyboard, hold down the Shift key and press the - (hyphen) key.

Creating the "_" symbol on a smartphone or tablet

To create an underscore on a smartphone or tablet, open the keyboard, access the numbers (123) keys, then access the (#+=) or symbols (sym) section. Press your finger on the "_" key.

What is an underscore used for on a computer?

The underscore is commonly used as an alternative to the space key when a space is not allowed. For example, in computer programming, a variable may be named $my_variable, using an underscore instead of a space because spaces are not permitted in a variable name.

Underscore vs. underline

Underlined word

An underscore is different than an underline. If you are trying to underline any letter, number, or other text, the underline feature should be used. The underscore, by contrast, takes the place of another character, like a number, letter, or symbol; it cannot be used under another character.

Underscore in file names

It is not uncommon to use an underscore in a file name in place of a space, especially on the Internet. However, if you're concerned about SEO, we suggest using a hyphen instead of an underscore when separating keywords. Google treats an underscore as a combiner and a hyphen as a separator. So "computer_hope" is treated as "computerhope," and "computer-hope" is treated as "computer hope."

Underscore in an e-mail address

With most e-mail addresses, one or more underscores can be used in an e-mail address to make it easier to read a username. For example, "[email protected]" is harder to read than "[email protected]" However, not all e-mail services allow underscores (e.g., Gmail doesn't allow underscores).

Should I use underscores in my e-mail?

For services that do support underscores in an e-mail address, consider the cons of using an underscore. Many people find having underscores in an e-mail address or username annoying because it's difficult to type. Also, not everyone knows how to type an underscore which means they may not enter the correct e-mail address.

We recommend avoiding underscores when creating an e-mail address. It may be easier to read, but it can be difficult to type and make it difficult to share.

What is the other symbol on the underscore key?

On U.S. keyboards, the underscore key is shared with the hyphen key, which may be shown next to or above the hyphen symbol. To create the underscore, hold down Shift while also pressing - above the P key.

Is the underscore punctuation?

When the underscore was first introduced on a typewriter, it was used to underline text that had been already typed. Because an underline is not punctuation, the underscore is a character and not punctuation.

CamelCase, Keyboard terms, White space