↔
↔ Left Right Arrow
The left-right arrow (↔) points both ways — a two-way relationship in a diagram, and “if and only if” in logic.
Also known as: left right arrow, double arrow, two sided arrow, bidirectional arrow.
Codes
| Symbol | ↔ | |
| Double (implies both ways) | ⇔ · U+21D4 | |
| Unicode | U+2194 | |
| HTML entity (named) | ↔ | |
| HTML entity (decimal) | ↔ | |
| HTML entity (hex) | ↔ | |
| CSS | \2194 | |
| LaTeX | \leftrightarrow | |
| Windows Alt code | Alt + 29 |
How to type ↔ (Left Right Arrow)
WindowsAlt + 29
Hold Alt and type 29 on the numeric keypad, then release Alt (or type 2194 then Alt + X in Word).
Mac
No default keystroke. Open Character Viewer (Control + Cmd + Space) and search “left right arrow”, or copy ↔ above.
Microsoft Word2194, Alt + X
Type 2194, then press Alt + X to convert it to ↔.
Google Docs
Insert → Special characters, then search “left right arrow”.
LaTeX\leftrightarrow
Use \leftrightarrow in math mode. \Leftrightarrow gives the double arrow ⇔, and \iff is the same thing with wider spacing.
Usage
- ↔ marks a two-way relationship: a bidirectional link in a diagram, a swap, or a range.
- In logic, ↔ is the biconditional — “if and only if”. P ↔ Q is true exactly when P and Q have the same truth value.
- Which arrow to use: ↔ (U+2194) is the plain arrow. ⇔ (U+21D4) is the double arrow, used for logical equivalence between statements — many authors reserve ↔ for the connective inside a formula and ⇔ for the claim about formulas. They are different characters either way.
- The Alt code continues the low-range family from the original IBM PC set: ↑ is Alt + 24, ↓ is 25, → is 26, ← is 27 and ↔ is 29.