Chi — χ Greek Letter Symbol
χ
Chi — χ / Χ
22nd letter of the Greek alphabet · pronounced /kaɪ/
StatisticsPhysicsMathematicsEngineering
Copy symbol
χ
Lowercase chi
Χ
Uppercase Chi
Technical reference
| Unicode (lowercase) | U+03C7 |
| Unicode (uppercase) | U+03A7 |
| HTML entity | χ |
| HTML decimal | χ |
| LaTeX | \chi |
| Python / Unicode escape | \u03c7 |
| Alt code (Windows) | Alt + 967 |
Uses in science & engineering
Chi-squared distribution (χ²)
Widely used distribution in statistical hypothesis testing and goodness-of-fit tests.
\(\chi^2 = \sum \frac{(O_i – E_i)^2}{E_i}\)
Electric susceptibility
Measure of how easily a material polarises in response to an electric field.
\(\mathbf{P} = \varepsilon_0 \chi_e \mathbf{E}\)
Magnetic susceptibility
Degree to which a material can be magnetised in an external magnetic field.
\(\mathbf{M} = \chi_m \mathbf{H}\)
Euler characteristic (topology)
Topological invariant of a surface: χ = V − E + F.
\(\chi = V – E + F\)
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 “chi”
Microsoft Word
Type 03c7 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