The radical symbol (√), commonly known as the square root sign, is a fundamental mathematical notation representing the principal root of a number. Whether you are a student drafting a math assignment, a scientist writing a research paper, or a web developer coding mathematical expressions, knowing how to input this symbol efficiently is essential. While it is not a standard key on most QWERTY layouts, every modern operating system and software suite provides multiple ways to access it.

This guide provides an exhaustive breakdown of how to type the radical symbol on Windows, macOS, Linux, mobile devices, and within specialized applications like Microsoft Word and Google Docs.

Quick Answer: The Fastest Ways to Get the Radical Symbol

If you need the symbol immediately, the easiest method is to copy and paste it: √.

For those who prefer keyboard shortcuts, here are the most common ones:

  • Windows: Hold Alt and type 251 on the numeric keypad.
  • Mac: Press Option + V.
  • Microsoft Word: Type 221A and then press Alt + X.
  • iOS/Android: Look for it in the math/symbols sub-menu of your keyboard.

How to Type the Radical Symbol on Windows

Windows offers several methods to input special characters. The best method depends on whether your keyboard has a dedicated numeric keypad and which application you are using.

Using Alt Codes (Requires Numeric Keypad)

The Alt code method is a legacy feature that remains the fastest way to type symbols in Windows. However, it requires a keyboard with a physical Numpad.

  1. Ensure Num Lock is turned on.
  2. Press and hold the Alt key.
  3. While holding Alt, type 251 on the numeric keypad (the numbers on the top row will not work).
  4. Release the Alt key, and the √ symbol will appear.

Technical Note: This method uses the OEM character set. In some environments, specifically those using different code pages, Alt + 251 might produce a different character. If this happens, you may need to use the Unicode method described below.

The Windows Emoji and Symbol Panel

For users on Windows 10 and 11, the Emoji Panel is a modern alternative that doesn't require memorizing codes.

  1. Place your cursor where you want the symbol.
  2. Press Windows Key + . (Period) or Windows Key + ; (Semicolon).
  3. Click on the Symbols icon (the Greek Omega Ω).
  4. Navigate to the Math Symbols category (represented by a plus/minus sign).
  5. Scroll down to find the square root symbol (√) and click it.

Character Map

The Character Map is a utility that allows you to view every character available in a specific font. This is useful if you want to ensure the radical symbol matches the styling of your text.

  1. Press the Start button and type "Character Map."
  2. Select the font you are using (e.g., Arial or Times New Roman).
  3. Check the "Advanced view" box.
  4. In the "Search for" field, type "square root" and hit Enter.
  5. Double-click the √ symbol and then click "Copy."

Microsoft Word: The Alt+X Method

Microsoft Word has a unique way of handling Unicode characters. Every character has a hexadecimal code; for the radical symbol, it is 221A.

  1. Type 221A in your Word document.
  2. Immediately press Alt + X.
  3. The text 221A will instantly transform into √.

This method is highly reliable because it bypasses the regional limitations of Alt codes and works on laptops without a numeric keypad.

How to Type the Radical Symbol on macOS

macOS is generally more intuitive when it comes to typing special characters, as many are mapped directly to the Option key.

The Standard Keyboard Shortcut

The fastest way to type a square root on a Mac is:

  • Option + V

This shortcut is universal across the operating system, working in Safari, Notes, Pages, and third-party apps like Slack or Discord.

Using the Character Viewer

If you need a variation of the radical symbol (such as a cube root or a stylistic alternative), use the Character Viewer.

  1. Press Control + Command + Spacebar.
  2. Type "square root" into the search bar at the top.
  3. The search results will show the standard radical sign (√).
  4. Double-click the symbol to insert it.

Unicode Hex Input

For power users who need to enter specific Unicode characters by their hex code:

  1. Go to System Settings > Keyboard > Input Sources.
  2. Add Unicode Hex Input.
  3. Switch to this input method from the menu bar.
  4. Hold Option and type 221A.

Typing the Radical Symbol on Mobile Devices

Mobile keyboards prioritize emojis and common punctuation, so mathematical symbols are often hidden behind layers of menus.

iPhone and iPad (iOS)

  1. Tap the 123 button to switch to the numeric layout.
  2. Tap the #+= button to access secondary symbols.
  3. Locate the √ symbol.
  4. If it is not visible, it may depend on your regional keyboard settings. A common workaround is to use the Text Replacement feature:
    • Go to Settings > General > Keyboard > Text Replacement.
    • Tap the + sign.
    • Paste √ into the "Phrase" field.
    • Type "sqrt" into the "Shortcut" field.
    • Now, whenever you type "sqrt," the iPhone will suggest the √ symbol.

Android Devices (Gboard/Samsung Keyboard)

  1. Open the keyboard and tap the ?123 key.
  2. Tap the =< key to see more mathematical symbols.
  3. The radical symbol (√) is usually located in this panel.
  4. Alternatively, you can long-press the caret (^) or other math symbols to see if the radical sign appears as a pop-up option.

Using the Radical Symbol in Professional Software

Standard text characters for the radical symbol often lack the "vinculum"—the horizontal bar that extends over the numbers inside the root. For professional documents, you should use equation editors.

Microsoft Office (Equation Editor)

In Word, Excel, or PowerPoint, using the Equation Editor allows you to create mathematically correct radicals.

  1. Press Alt + = to open the Equation box.
  2. Type \sqrt followed by a Space. This creates a radical symbol with a placeholder box.
  3. Type the number or expression inside the box.
  4. For cube roots or nth roots, type \root(n)(x) and press Space.

Google Docs

Google Docs does not support the Alt+X method, but it has a built-in symbol picker.

  1. Go to Insert > Special Characters.
  2. Search for "square root."
  3. Select the symbol to insert it.
  4. Alternatively, use Insert > Equation to use the LaTeX-style equation bar.

LaTeX for Academic Writing

LaTeX is the gold standard for scientific typesetting. The radical symbol is handled using the \sqrt command.

  • Square Root: \sqrt{x}
  • N-th Root: \sqrt[n]{x} (e.g., \sqrt[3]{8} for a cube root).

When compiled, LaTeX automatically scales the size of the radical symbol and the length of the horizontal bar to perfectly fit the content inside.

Radical Symbol in Web Development and Coding

If you are building a website, you should use HTML entities or Unicode escapes to ensure the symbol renders correctly across different browsers and character encodings.

HTML Entities

In HTML, you can use the named entity or the decimal/hexadecimal code:

  • Named Entity: &radic; (√)
  • Decimal Code: &#8730;
  • Hex Code: &#x221A;

CSS and JavaScript

In a CSS file, you can insert the symbol using its Unicode hex value within the content property: