Kappa Symbol Κ κ Copy and Paste

Kappa Symbols — Copy Them Here

Uppercase Kappa: Κ

Lowercase Kappa: κ

What Is the Kappa Symbol?

Kappa (κάππα) is the tenth letter of the Greek alphabet. In the Greek numeral system, it has a value of 20. The uppercase form is Κ and the lowercase is κ. It evolved from the Phoenician letter kaph, which meant "palm of the hand."

Unicode Codes

• Uppercase Κ: U+039A
• Lowercase κ: U+03BA
• HTML uppercase: Κ
• HTML lowercase: κ

Keyboard Shortcuts

Windows

• Hold Alt and type 954 on the numeric keypad for lowercase κ
• Hold Alt and type 922 on the numeric keypad for uppercase Κ

Mac

• Lowercase κ: Press Option + K

iPhone and Android

Add the Greek keyboard in your phone settings, switch to it, and type "k" to get κ. Or just copy-paste from above.

Where Kappa Is Used

Mathematics

• Curvature — in differential geometry, κ represents the curvature of a curve at a given point
• Kappa number — in the paper industry, measures the lignin content of wood pulp
• Kappa statistic — in categorical agreement testing (see Statistics section)

Physics

• Coulomb's constant — sometimes denoted κ in electrostatics
• Thermal conductivity — κ is used for thermal conductivity in physics and engineering
• Compressibility — the isothermal compressibility of a material is often written as κ
• Einstein gravitational constant — appears in Einstein's field equations

Chemistry

• Degree of dissociation — in physical chemistry, κ can represent the degree of ionic dissociation
• Molar extinction coefficient — sometimes represented by κ in spectroscopy

Statistics

• Cohen's kappa (κ) — measures inter-rater agreement for categorical items. Values range from -1 to 1, where 1 means perfect agreement, 0 means no agreement beyond chance, and negative values mean systematic disagreement
• Fleiss' kappa — extends Cohen's kappa to multiple raters

Medicine and Biology

• Kappa light chain — one of the two types of immunoglobulin light chains in antibodies
• Kappa opioid receptor — a protein that binds opioid-like compounds in the brain

Cohen's Kappa Explained Simply

Cohen's kappa measures how well two people agree when classifying things into categories, accounting for agreement that happens by chance. For example, if two doctors diagnose the same set of patients, kappa tells you whether their agreement is better than random luck. A kappa above 0.8 is strong agreement, 0.6-0.8 is moderate, and below 0.6 is weak.

Kappa in Internet Culture

On the streaming platform Twitch, "Kappa" is one of the oldest and most recognizable emotes — a grayscale face used to indicate sarcasm or joking. It originated from a photo of former Justin.tv employee Josh DeSeno and has nothing to do with the Greek letter itself.

Related Greek Letters

Looking for more Greek symbols? Check out our guides for Alpha (α), Gamma (γ), and Zeta (ζ).