⇔

If and Only If Arrow Symbol (⇔)

Copy and paste the if and only if arrow ⇔ with one click

About the If and Only If Arrow Symbol

Last reviewed on October 31, 2026

⇔ is a double-headed double arrow that says two statements are equivalent. P ⇔ Q means each implies the other. Proofs often write it as iff, and definitions use it to restate a condition in a precise way.

Its official Unicode name is Left Right Double Arrow. Browse the Arrows page for related characters.

How to Type If and Only If Arrow on a Keyboard

Windows: Type 21D4 then press Alt+X in Word; in other apps, copy ⇔ from this page and paste it. It has no classic Alt code

Mac: Press Ctrl+Cmd+Space to open the Character Viewer, then search for the symbol by name

Microsoft Word: Type 21D4 then press Alt+X

Phone & tablet: Copying ⇔ from this page is fastest — see our mobile typing guide

Frequently Asked Questions

How do I type if and only if arrow ⇔ on Windows?

Type 21D4 then press Alt+X in Word; in other apps, copy ⇔ from this page and paste it. It has no classic Alt code. You can also copy ⇔ straight from this page.

How do I type ⇔ on a Mac?

Press Ctrl+Cmd+Space to open the Character Viewer, then search for the symbol by name.

What is the Unicode and HTML code for if and only if arrow?

It is Unicode code point U+21D4, named Left Right Double Arrow. In HTML, use ⇔ or the numeric reference ⇔.