Kappa (κ) in LaTeX
In LaTeX maths mode, \kappa produces the lowercase Greek letter kappa (κ), and \varkappa produces the curly variant (ϰ). Uppercase Kappa is identical to a Latin K, so there is no \Kappa command.
LaTeX command
\kappaNot the symbol you meant? Draw it to find the command →
Kappa, \kappa, is a workhorse symbol in the mathematical sciences. In differential geometry it is the curvature of a curve, in numerical linear algebra it is the condition number \kappa(A) of a matrix, and in physics it denotes thermal or electrical conductivity, compressibility and similar material constants. It must be used in maths mode.
The variant \varkappa gives a more rounded, cursive kappa (ϰ). In a full LaTeX document it requires the amssymb package, part of the AMS bundle; KaTeX supports \varkappa natively. Use it when you need a kappa visually distinct from \kappa, or to match a particular field's convention.
There is no uppercase command: the capital Greek Kappa is drawn as a Roman K, so you simply type K, or \mathrm{K} for an upright roman capital. Kappa in maths mode is italic by default, the usual style for a variable or a function name like \kappa(A).
Other forms
\kappalowercase kappa\varkappacurly / variant formExamples
$\kappa$lowercase kappa inline
$\kappa(A) = \lVert A \rVert \, \lVert A^{-1} \rVert$the condition number of a matrix
$\kappa = \frac{1}{R}$curvature as the reciprocal of the radius
$\varkappa$the curly variant (needs amssymb in a document)
Tips and common mistakes
\varkappaneeds the amssymb package in a LaTeX document; it works out of the box in KaTeX.- There is no
\Kappa; uppercase Greek Kappa is a Latin K, so type K. - All kappa commands require maths mode; wrap them in .
- In numerical work write the condition number as
\kappa(A), matching the standard notation. - Do not confuse
\kappa(κ) with a Latin k; the Greek form has a distinct open shape.
Working from handwritten notes?
LatexNotes turns a photo or PDF of handwritten mathematics into clean, compilable LaTeX - graphs and all. Free to try, no sign-up.
Convert your maths to LaTeX →FAQ
How do I get the curly kappa in LaTeX?
Use \varkappa (ϰ). In a full document load the amssymb package; in KaTeX and most inline renderers it works without any package.
Is there an uppercase kappa command?
No. Capital Greek Kappa is identical to the Latin K, so LaTeX has no \Kappa; type K, or \mathrm{K} for an upright capital.
What does kappa mean in linear algebra?
Kappa denotes the condition number \kappa(A) of a matrix, a measure of how sensitive the solution of a linear system is to errors in the data.