κ Kappa Symbol
Kappa (κ) is the tenth Greek letter — Cohen's κ for inter-rater agreement in statistics, curvature in geometry, and the condition number κ(A) in numerical computing.
Also known as: kappa symbol, kappa sign, symbol for kappa, greek small letter kappa.
Codes
| Symbol | κ | |
| Uppercase | Κ · U+039A | |
| Unicode | U+03BA | |
| HTML entity (named) | κ | |
| HTML entity (decimal) | κ | |
| HTML entity (hex) | κ | |
| CSS | \03BA | |
| LaTeX | \kappa |
How to type κ (Kappa Symbol)
Kappa has no short Alt code — it is not in the legacy code pages that Alt + nnn draws on. In Word, type 03BA then Alt + X. Elsewhere press Win + . (period) and search “kappa”, or copy κ above. (Alt + 954 works where decimal-Unicode input is supported.)
No default keystroke. Open Character Viewer (Control + Cmd + Space), search “greek small letter kappa”, and double-click κ.
Type 03BA, then press Alt + X to convert it to κ.
Insert → Special characters, then search “kappa”.
Use \kappa in math mode; \varkappa (amssymb) gives the curly variant ϰ. There is no \Kappa — uppercase kappa is a Latin K shape, so just write K.
Usage
- In statistics, Cohen's κ measures agreement between two raters beyond what chance alone would produce. κ = 1 is perfect agreement, κ = 0 is chance-level, and negative values mean the raters disagree more than chance.
- In geometry κ is curvature — the reciprocal of the radius of the osculating circle, so a tighter bend means a larger κ.
- In numerical linear algebra κ(A) is the condition number of a matrix: a large κ(A) means the system is ill-conditioned and small input errors blow up in the solution.
- In physics κ is thermal conductivity, and in electronics the dielectric constant of an insulator.
- Which one to use: κ (U+03BA) is the Greek letter. ϰ (U+03F0) is the curly “kappa symbol” variant used in some physics conventions, and the Latin k is a different character entirely — copying a Latin k into an equation will typeset and search differently even though it looks close.