Epsilon — ε Greek Letter Symbol
ε
Epsilon — ε / Ε
5th letter of the Greek alphabet · pronounced /ˈɛpsɪlɒn/
MathematicsPhysicsEngineeringElectromagnetism
Copy symbol
ε
Lowercase epsilon
Ε
Uppercase Epsilon
Technical reference
| Unicode (lowercase) | U+03B5 |
| Unicode (uppercase) | U+0395 |
| HTML entity | ε |
| HTML decimal | ε |
| LaTeX | \epsilon |
| Python / Unicode escape | \u03b5 |
| Alt code (Windows) | Alt + 949 |
Uses in science & engineering
Strain (structural engineering)
Ratio of deformation to original length. Fundamental in stress-strain analysis.
\(\varepsilon = \frac{\Delta L}{L_0}\)
Permittivity
Measure of a material ability to store electrical energy in an electric field.
\(D = \varepsilon \cdot E\)
Small positive number (mathematics)
Used in epsilon-delta definitions of limits and continuity in calculus.
\(|f(x) – L| < \varepsilon\)
Eccentricity (orbital mechanics)
Describes the shape of an elliptical orbit.
\(r = \frac{a(1-\varepsilon^2)}{1+\varepsilon\cos\theta}\)
Emissivity (thermodynamics)
Ratio of radiation emitted by a surface to that of a perfect black body.
\(Q = \varepsilon \sigma A T^4\)
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 “epsilon”
Microsoft Word
Type 03b5 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