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What is an Underscore Symbol | In-Depth Guide

What is an Underscore Symbol | In-Depth Guide
Windows Keyboard

Creating the Underscore Symbol on Any Device: A Step-by-Step Guide


The underscore symbol " _ " is a versatile character used in various computing and programming contexts. It plays a critical role in file naming, email addresses, and coding. This blog will explore how to create the underscore symbol on different devices, its uses, and its distinctions from similar symbols.

How to Create the Underscore Symbol

On Windows

What is an Underscore Symbol | In-Depth Guide
Underscore Symbol

Creating an underscore on a Windows keyboard is simple:

  • Press the Shift key and the hyphen (-) key simultaneously.

  • Hold down the Alt key and type 95 on the numeric keypad.

On Smartphones and Tablets

iOS Devices:

1. Open the keyboard in any text field.

2. Tap the 123 key to switch to the numeric and symbols keyboard.

3. Tap the #+= key to reveal more symbols.

4. Tap the underscore "_" key.

Android Devices:

1. Open the keyboard in any text field.

2. Tap the ?123 key to switch to the numeric and symbols keyboard.

3. Tap the =\< key to access additional symbols.

4. Tap the underscore "_" key.

Uses of the Underscore Symbol

On a Computer

  • File Names: The underscore is often used to separate words in file names, ensuring compatibility across different operating systems (e.g., `my_document.txt`).

  • Email Addresses: While underscores can be used in email addresses, they are less common than periods or hyphens (e.g., ``).

  • Programming: In coding, underscores can serve various purposes, such as indicating private variables or separating words in identifiers (e.g., `first_name`).

In Programming

  • Variable Naming: Many programming languages use underscores to separate words in variable names (e.g., `user_name`).

  • Constants: In languages like Python, underscores are used to define constants or private variables (e.g., `_PRIVATE_VARIABLE`).

  • Whitespace Replacement: Underscores replace spaces in contexts where spaces are not allowed (e.g., URLs).

Underscore vs. Underline

The underscore (_) is a character used in text, while an underline is a formatting option that draws a line beneath text. They serve different purposes and should not be confused:

  • `_myfile.txt`

  • Underlined text


  • The underscore is a single character placed at the text level, whereas an underline is a line beneath the text.

  • The underscore is used in coding and file names, while underlining is used for emphasis in written documents.

Underscore in File Names

Using underscores in file names is a common practice to improve readability and ensure compatibility across different operating systems. Spaces in file names can cause issues in command-line interfaces and scripts, making underscores a preferred alternative (e.g., `my_document.txt` instead of `my document.txt`).


  • Good: `my_project_report_2023.docx`

  • Problematic: `my project report 2023.docx`

Underscore in an Email Address

While valid, underscores in email addresses are less common than periods or hyphens. Some email clients and services might misinterpret underscores, leading to potential issues.


Valid: ``

Preferred: ``

Should You Use Underscores in Your Email?

It's generally advisable to avoid using underscores in your email address if possible. They can be mistaken for spaces or other characters and may not be supported by all email systems. Periods or hyphens are typically safer choices.

Is the Underscore Punctuation?

Yes, the underscore is considered a punctuation character. It is used primarily in digital contexts, such as programming and file naming, rather than traditional writing.

Additional Details

Historical Context

The underscore originated from typewriters, where it was used for underlining by typing the underscore beneath text. This practice has evolved with the advent of digital text editing, where the underscore has found new uses in computing and programming.

Common Misconceptions

  • In programming and file naming, underscores replace spaces to avoid errors in code execution and file path recognition.

  • Not all systems interpret underscores the same way, particularly in email addresses and URLs.

Tips for Using Underscores

  1. Use underscores to enhance clarity in variable names and file names.

  2. Maintain consistent use of underscores in your projects to avoid confusion and errors.

  3. While useful, avoid overusing underscores as it can make text harder to read.

What is an Underscore Symbol | In-Depth Guide


The underscore symbol is a versatile and essential character in the world of computing. Understanding how to create and use it effectively can enhance your efficiency in file management, programming, and digital communication. Whether you are a professional coder or a casual user, mastering the underscore symbol is a valuable skill in today's digital age.

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