Theta Symbol θ Copy and Paste

Tap θ to copy the Greek letter that names an angle: sin θ, cos θ, θ = 45°. The table gives the typing routes on each platform, and the notes cover the capital Θ, the script ϑ and the lookalikes ө and 0.

θ

GREEK SMALL LETTER THETA

U+03B8 · tap the symbol to copy

How to Type the Theta Symbol

UnicodeU+03B8 GREEK SMALL LETTER THETA
HTMLθ or θ
WindowsWin + . (emoji panel) → Symbols, or type 03B8 then Alt + X in Word
MacNo Option-key shortcut; add the Greek keyboard in System Settings → Keyboard → Input Sources and press U, or use Control + Command + Space
iPhoneAdd the Greek keyboard (Settings → General → Keyboard → Keyboards) and tap U; or set up a Text Replacement
AndroidGboard: add a Greek layout and tap U, or add a shortcut in Gboard → Dictionary
LaTeX\theta (\Theta for Θ, \vartheta for ϑ)

Theta Symbol Variants and Lookalikes

Using the Theta Symbol

Theta is the eighth letter of the Greek alphabet, an oval with a horizontal bar, and in mathematics it is the default name for an angle. Trigonometry textbooks write sin θ, cos θ and tan θ, polar coordinates use (r, θ), and the angle between two vectors is θ in the dot-product formula a · b = |a||b| cos θ. ### Other meanings

θ, ϑ and Θ

Unicode encodes three shapes. θ is the standard small letter. ϑ, the GREEK THETA SYMBOL, is a cursive form with an open top that mathematicians use when a second theta-like variable is needed, and it is the usual letter for the Jacobi theta functions; LaTeX produces it with \vartheta. Capital Θ is the letter used in Big Theta, and ϴ is a separate capital variant with a shorter bar that exists mainly for maths fonts. Choose θ unless you have a specific reason to want one of the others.

Typography and spacing

Like any Greek variable, θ is set italic in typeset maths and upright in prose. Function names stay upright with a thin space before the argument: sin θ, not sinθ. Degrees follow the value with no space (θ = 30°), and when θ multiplies a number the number comes first (2θ). ### Typing it

No Latin-1 Alt code exists for theta on Windows; open the Win + . panel or, in Word, type 03B8 and press Alt + X (0398 gives capital Θ). The Mac offers no Option shortcut either; add the Greek keyboard and press U, which is where theta sits on the Greek layout, or find it in the Character Viewer. iPhone and Android users add the same Greek keyboard, where U types θ and Shift + U types Θ. The HTML entity is θ, and in LaTeX it is \theta.

Lookalikes and culture

Two unrelated letters are visually identical in many fonts: the Cyrillic barred o ө of Kazakh and Mongolian, and the IPA vowel ɵ. Copying a "theta" from a Cyrillic web page will give you one of those, which breaks search and screen-reader output, so take the character from this page instead. Culturally θ is the letter of Theta Chi, Kappa Alpha Theta and other Greek-life chapters, and, thanks to Big Theta and the ML parameter vector, a favourite in computer-science handles beside the lambda symbol and the sigma symbol. Its rounded shape suits the bubble fonts generator, and for the angle sign itself see the degree symbol page.

Theta Symbol FAQ

How do I type the theta symbol in Word?

Type 03B8 where you want it and press Alt + X; Word swaps the code for θ. For the capital Θ the code is 0398, and for the script ϑ it is 03D1. Inside an equation, \theta followed by a space also converts automatically.

Is there a keyboard shortcut for θ on a Mac?

No Option-key combination gives theta. Add the Greek input source in System Settings → Keyboard, switch to it and press U. Alternatively, open the Character Viewer with Control + Command + Space and search "theta".

What does θ mean in trigonometry?

It is the conventional name for an angle, especially the angle whose sine, cosine or tangent you are finding. It carries no fixed value; θ is simply a variable that ranges over angles, usually measured in degrees or radians.

What is the difference between θ and ϑ?

θ is the ordinary lower-case letter. ϑ is a cursive variant, encoded separately as GREEK THETA SYMBOL, with an open, looping top. Mathematicians use it as a second theta-like variable or for the Jacobi theta functions; in ordinary writing, use θ.

What does Θ(n) mean in computer science?

Big Theta describes a tight asymptotic bound. Θ(n) means an algorithm's running time grows proportionally to n, neither faster nor slower, whereas Big O gives only an upper bound.

How do I type θ on an iPhone?

Add the Greek keyboard in Settings → General → Keyboard → Keyboards → Add New Keyboard, then switch to it with the globe key and tap U. Shift + U gives the capital. A text replacement is quicker if you use it often.