Arrow Left Right Double Arrow
About this character
The character ⇔ is known as Arrow Left Right Double Arrow and carries the Unicode code point U+21D4, which is 8660 in decimal. It belongs to the Arrows block (U+2190–U+21FF), which gathers single, double and curved arrows used in typography, mathematics and user interfaces.
In memory, ⇔ takes 3 bytes in UTF-8 (0xE2 0x87 0x94) and 1 in UTF-16 (0x21D4). That difference is why badly configured forms or databases garble this character: they assume one byte per character.
How to type ⇔
| System | What to do |
|---|---|
| Windows | In Word or WordPad, type 21D4 and press Alt + X to turn the code into the character. |
| macOS | On a Mac, open the Character Viewer with Ctrl + ⌘ + Space and search for “Arrow Left Right Double Arrow”. |
| Linux | On Linux (GTK), type Ctrl + ⇧ + U, 21D4 then press Enter. |
| HTML / Web | In an HTML page, write ⇔. Use \21D4 in CSS, \u21D4 in JavaScript and \u21D4 in Python. |
| On this site | The simplest route is the Copy button above: the character goes straight to your clipboard, ready to paste anywhere. |
Keyboards that include ⇔
This character is not on any common physical layout, so the Copy button above is the quickest way to get it into a document.
Codes and encodings
| Property | Value |
|---|---|
| Code point | U+21D4 |
| Unicode block | Arrows (U+2190–U+21FF) |
| Decimal | 8660 |
| Hexadecimal | 0x21D4 |
| Octal | 020724 |
| Binary | 10000111010100 |
| UTF-8 bytes | 0xE2 0x87 0x94 |
| UTF-16 units | 0x21D4 |
| Named HTML entity | ⇔ |
| Decimal HTML entity | ⇔ |
| Hex HTML entity | ⇔ |
| CSS escape | \21D4 |
| JavaScript escape | \u21D4 |
| Python escape | \u21D4 |
| URL encoding | %E2%87%94 |
Frequently asked questions
What is the Unicode code for ⇔?
Its code point is U+21D4, which is 8660 in decimal and 020724 in octal. In HTML you can write it as ⇔ or ⇔.
Why does ⇔ show up as a box or a question mark?
An empty box means the font has no glyph for U+21D4. The character is still in the text: switching to a font that covers the block (Noto, DejaVu or Segoe UI Symbol) makes it appear.
Can I use ⇔ in a filename, a URL or a password?
In a URL it must be encoded as %E2%87%94. Modern filesystems accept it, though it is still risky when moving files between systems. For passwords, some forms reject non-ASCII characters outright.