Square Root Symbol (√) — Meaning, Copy & Paste, and How to Type It
Copy the Square Root Symbol
Here is the square root symbol ready for you to copy and paste:
√ — Copy this symbol: √
Unicode: U+221A | HTML entity: √ | LaTeX: \sqrt
Just click or tap the symbol above, copy it, and paste it wherever you need it — documents, social media, emails, or code.
What Is the Square Root Symbol?
The square root symbol (√) is a mathematical notation that represents the square root of a number or expression. When you see √9, it means the number that, when multiplied by itself, equals 9 — which is 3. The formal name for this symbol is the "radical sign" or "radix."
The symbol has a rich history dating back to the 1500s. It evolved from the letter "r" (for "radix," the Latin word for root). German mathematician Christoph Rudolff first used the modern √ symbol in his 1525 book "Coss." Over time, the horizontal bar (called the vinculum) was added on top of the expression under the root to clarify what was being rooted.
Today, the square root symbol is used everywhere in mathematics, science, engineering, statistics, and even everyday calculations. It is one of the most widely recognized mathematical symbols in the world.
How to Type the Square Root Symbol on Windows
There are several ways to type √ on a Windows computer:
Alt Code method: Hold down the Alt key and type 251 on the numeric keypad. Release the Alt key and √ will appear. Make sure Num Lock is turned on. This method works in most Windows applications including Word, Notepad, browsers, and email clients.
Character Map: Press the Windows key, type "Character Map," and open the app. Search for "square root" or find it in the Mathematical Operators section. Select √, click Copy, and paste it into your document.
Microsoft Word shortcut: In Word, you can type 221A and then press Alt+X. The code will convert to √. You can also go to Insert → Symbol → More Symbols and find it under Mathematical Operators.
Windows Emoji Picker: Press Win + Period (.) to open the emoji picker. Switch to the symbols section and look for √.
How to Type the Square Root Symbol on Mac
On macOS, typing the square root symbol is straightforward:
Keyboard shortcut: Press Option + V. This is the quickest way to type √ on a Mac. It works in almost every application — TextEdit, Pages, Safari, Mail, and more.
Character Viewer: Press Control + Command + Space to open the Character Viewer. Search for "square root" or browse to Math Symbols. Double-click √ to insert it at your cursor position.
Unicode Hex Input: If you have the Unicode Hex keyboard enabled in System Settings → Keyboard → Input Sources, you can hold Option and type 221A to produce √.
How to Type the Square Root Symbol on iPhone and iPad
Typing √ on iOS is simple once you know where to look:
Using the symbols keyboard: Open the keyboard in any app. Tap the "123" key to access numbers, then tap the "#+=" key. You will find √ in the symbols layout. Tap it to insert it.
Text Replacement: Go to Settings → General → Keyboard → Text Replacement. Create a shortcut where the phrase is √ and the shortcut is something like "sqroot". From then on, typing "sqroot" will auto-replace with √.
Copy and paste: The easiest method for occasional use — just copy √ from this page and paste it wherever you need it.
How to Type the Square Root Symbol on Android
On Android devices, you have a few options:
Google Keyboard (Gboard): Tap the "?123" key, then tap "=\<" to access more symbols. Look for √ in the extended symbols panel. The exact location varies by keyboard version.
Long-press method: On some keyboards, long-pressing the caret symbol (^) may reveal √ as an option.
Clipboard method: Copy √ from this page to your clipboard, then paste it in any app. This is the most reliable method across all Android devices and keyboard apps.
Square Root Symbol Unicode Details
Here are the technical details for the square root symbol:
Unicode code point: U+221A
Unicode name: Square Root
HTML entity: √ or √
CSS content: \221A
JavaScript: \u221A
LaTeX: \sqrt
UTF-8 encoding: E2 88 9A
UTF-16 encoding: 221A
The square root symbol lives in the Mathematical Operators Unicode block (U+2200 to U+22FF), which contains many commonly used math symbols.
Related Mathematical Root Symbols
Beyond the basic square root, there are related symbols you might find useful:
∛ — Cube root (U+221B). Represents the cube root of a number. For example, ∛27 = 3.
∜ — Fourth root (U+221C). Represents the fourth root of a number.
For nth roots beyond the fourth, mathematicians typically use a general radical notation with a small index number placed in the angle of the radical sign, rather than a dedicated Unicode character.
Common Uses of the Square Root Symbol
The square root symbol appears in many fields and contexts:
Mathematics: Used extensively in algebra, geometry, calculus, and trigonometry. The Pythagorean theorem (a² + b² = c²) involves square roots when solving for sides of a right triangle.
Physics: Many physics formulas use square roots. For example, the formula for the period of a pendulum and the root-mean-square (RMS) calculations in electricity.
Statistics: The standard deviation formula uses the square root. It is also found in the normal distribution and various statistical tests.
Engineering: Square roots appear in structural calculations, signal processing, and electrical engineering formulas.
Finance: Used in calculating volatility, the Sharpe ratio, and various risk metrics in quantitative finance.
Computer Science: Algorithms often involve square root calculations for complexity analysis and graphics programming.
Square Root Symbol in HTML and Web Development
If you are working on a website and need to display the square root symbol, here are your options:
Use the HTML named entity: √ — this renders as √ in all modern browsers.
Use the numeric entity: √ — also renders as √ and has universal browser support.
Use the Unicode character directly: Simply paste √ into your HTML or use the Unicode escape \u221A in JavaScript.
In CSS, you can use it with the content property: content: "\221A"; to insert it via pseudo-elements.
Frequently Asked Questions
What is the Alt code for the square root symbol?
The Alt code is 251. Hold Alt and type 251 on the numeric keypad to get √.
Is the square root symbol the same as the check mark?
No, although they look similar. The check mark is ✓ (U+2713) while the square root is √ (U+221A). They have different Unicode code points and different meanings. The square root symbol typically has a longer, more pronounced top stroke.
Can I use the square root symbol in social media?
Yes. Copy √ and paste it into any social media platform — Twitter, Instagram, Facebook, TikTok, and others all support this Unicode character.
Why does Alt+251 not work on my laptop?
Most laptops do not have a dedicated numeric keypad. You may need to enable the hidden numpad (usually accessed via Fn + letter keys with small numbers printed on them) or use the Character Map instead.