Theta Symbol

Θ θ

The theta symbol (Θ / θ) is a letter of the Greek alphabet. This page covers its meaning across mathematics, science, and engineering, its Unicode code point, TeX command, and Windows Alt codes — and you can copy and paste the theta symbol with one click.

Uppercase Theta Symbol (Θ)

Symbol	Format	Data
Θ	Unicode	U+0398
Θ	HTML	Θ
Θ	CSS	\0398
Θ	JavaScript	\u0398
$\Theta$	TeX	\Theta
	SVG	Download ↓
	Image	Download ↓

Also known as: theta, uppercase theta, big theta, big theta notation, greek theta, asymptotic tight bound.

Θ is the capital form of the Greek letter theta. In computer science it denotes asymptotic tight bounds in the analysis of algorithms, the Θ of big-theta notation. In thermodynamics it occasionally labels a reference or Debye temperature, and it may serve as an angle or parameter set where the lowercase θ is already in use.

f(n) = \Theta(n \log n)

Lowercase Theta Symbol (θ)

Symbol	Format	Data
θ	Unicode	U+03B8
θ	HTML	θ
θ	CSS	\03b8
θ	JavaScript	\u03B8
$\theta$	TeX	\theta
	SVG	Download ↓
	Image	Download ↓

Also known as: greek theta, theta symbol, angle symbol, angle variable, o with line through it, lowercase theta, theta greek letter.

The Greek small letter theta (θ) is the eighth letter of the Greek alphabet. Its most familiar role is as the standard variable for an angle in trigonometry and geometry, and in polar and spherical coordinates it names one of the angular coordinates. It also appears as a parameter in statistics and in asymptotic notation, where Θ denotes a tight growth bound.

\sin^2 \theta + \cos^2 \theta = 1

Theta Symbol Alt Codes

On Windows, hold Alt and type the code on the numeric keypad, then release Alt. Num Lock must be on.

Alt Code	Case	Symbol
Alt233	Uppercase	Θ

Codes without a leading zero are legacy OEM codes; they depend on a US English Windows code page.

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Theta Symbol — Θ Greek Capital Letter Theta, θ Greek Small Letter Theta