How to type Square Root
To type Square Root (√), press Alt + 251 on Windows, holding Alt while typing the digits on the numeric keypad, or press Option + V on Mac, or write √ in HTML. On any system you can copy it from this page, or enter its codepoint U+221A directly: Ctrl+Shift+U then 221a on Linux, or 221a then Alt+X in Microsoft Word.
Square Root
- Copy it
- Unicode
- U+221A
- Windows
- Alt + 251
| Where | Shortcut | How |
|---|---|---|
| Windows | Alt + 251 | Hold Alt and type the number on the numeric keypad. |
| Mac | Option + V | Press the keys together. |
| HTML | √ | Paste this into HTML source. |
| Unicode | U+221A | SQUARE ROOT |
Other math symbols
Square Root is not the only name it goes by. People look for √ as radical and sqrt as well, and the search box on this site matches any of them, so you do not have to know which name Unicode chose.
√ lives in the Mathematical Operators block (U+2200-U+22FF), the core set of mathematical and logical operators. Within Unicode it is classified as Sm, a mathematical symbol. Software may lay it out with the spacing an operator expects.
What Square Root is used for
In mathematical notation √ does not stand on its own: it takes the expression it applies to and is drawn around it, growing to fit. LaTeX writes that as $\sqrt{x}$, where x is whatever is under it, which is why $\sqrt$ on its own is an error rather than a shorter way of saying the same thing.
Unicode publishes a second list of names for √ in CLDR, the keywords its own search data offers rather than the formal name, and they are radical, radix and surd. Those words are what somebody looking for this character is liable to type when Square Root is not the name they know it by, and the search on the symbol lists matches them as well as the Unicode name.
What √ gets confused with
√ has a twin that is a different character underneath. Search, sorting and anything that compares strings can tell them apart even where a reader cannot.
✓ (U+2713) is a check mark. At small sizes a tick in a table reads as a radical, and the radical has a horizontal arm that a tick does not.
What Unicode says about Square Root
The standard recognises √ under another name as well: radical sign. That is a formal alias, not a nickname, which is why it turns up in other people's documentation for the same codepoint.
The code chart points from √ to Check Mark. These are the characters the standard thinks you might have meant instead, which makes them the ones worth checking when Square Root looks nearly right but not quite.
How Square Root behaves in software
√ is East Asian Ambiguous: one column in a Western locale and two in a CJK one. That is why a table that lines up on your machine can break on somebody else's, with no change to the text at all. It carries no direction of its own, so in a line that mixes English with Arabic or Hebrew it takes the direction of the text around it rather than forcing one. It is a mirrored character: in right-to-left text it is drawn reversed, so it keeps pointing at what it pointed at.
What people ask about Square Root
How to type the square root symbol?
You can press Alt + 251 on Windows, with Num Lock on and the digits typed on the numeric keypad, or press Option + V on Mac. Either produces √.
What is the square root symbol?
√ is SQUARE ROOT, encoded at U+221A. It is distinct from check mark (U+2713), which the chart lists beside it precisely because they are confused for one another.
Every way to write Square Root
| Form | Value |
|---|---|
| Codepoint | U+221A |
| Decimal | 8730 |
| UTF-8 bytes | E2 88 9A |
| UTF-16 bytes | 22 1A |
| HTML entity | √ |
| HTML numeric | √ or √ |
| CSS | \221A |
| JavaScript | \u221A |
| Python | \u221A |
| URL-encoded | %E2%88%9A |
| LaTeX, in maths mode | $\sqrt{x}$ |
| LaTeX, in maths mode | $\surd$ |
| SVG | 221A.svg · (SIL Open Font License) |
If √ arrives as √
One character has become three, which is what a three-byte UTF-8 sequence looks like when each byte is read separately: E2 88 9A read as Windows-1252 gives exactly √. The text is intact and the damage is in the reading, so setting the reader to UTF-8 restores it and retyping does not. A rectangle instead of the mojibake means the opposite: the encoding is right and the font has no glyph at U+221A, which for a character this far outside Latin-1 is common in older office fonts.