Theta — θ Greek Letter Symbol
θ
Theta — θ / Θ
8th letter of the Greek alphabet · pronounced /ˈθiːtə/
MathematicsPhysicsEngineeringGeometry
Copy symbol
θ
Lowercase theta
Θ
Uppercase Theta
Technical reference
| Unicode (lowercase) | U+03B8 |
| Unicode (uppercase) | U+0398 |
| HTML entity | θ |
| HTML decimal | θ |
| LaTeX | \theta |
| Python / Unicode escape | \u03b8 |
| Alt code (Windows) | Alt + 952 |
Uses in science & engineering
Plane angle
Most common use: denotes an angle in geometry, trigonometry, and all branches of engineering.
\(s = r\theta\)
Phase angle
Describes the phase difference between two sinusoidal signals in AC circuit analysis.
\(v(t) = V_0 \sin(\omega t + \theta)\)
Temperature (thermodynamics)
Used as an alternative symbol for temperature, especially excess temperature above ambient.
\(\theta = T – T_{\infty}\)
Beam slope (structural engineering)
Angle of rotation of a cross-section of a beam under bending.
\(\theta = \frac{dv}{dx}\)
Polar coordinate angle
Angular coordinate in polar, cylindrical, and spherical coordinate systems.
\((r, \theta, \phi)\)
Related symbols
How to insert in applications
Windows
Best option: copy from this page.
Or press Win + . to open emoji & symbols panel.
Alt codes work only in Word/Notepad with NumLock on and English layout — not in browsers.
Or press Win + . to open emoji & symbols panel.
Alt codes work only in Word/Notepad with NumLock on and English layout — not in browsers.
macOS
Press ⌃⌘Space → Character Viewer → search “theta”
Microsoft Word
Type 03b8 then press Alt+X
Google Docs
Insert → Special characters → search by name
Excel
Insert → Symbol → Subset: Greek → select symbol
LaTeX
Use in math mode: $ … $
Python
Use Unicode escape or chr()
HTML / CSS
Use HTML entity or decimal code