Lambda Symbol (λ Λ): How to Type It Everywhere

Short answer: Tap a lambda below to copy it. To type it: on Windows, Alt + 955 = λ, Alt + 923 = Λ (numeric keypad); on Mac, open the Character Viewer (Control + Command + Space) and search “lambda,” or add the Greek input source; in Word, type 03BB then Alt + X; in HTML use λ / Λ; in LaTeX use \lambda / \Lambda.

Lambda is the 11th Greek letter — see the whole set in the Greek alphabet guide, or get any letter’s codes from the Alt Code Finder.

Lambda (Λ uppercase, λ lowercase) is the 11th letter of the Greek alphabet, and it’s one of the busiest symbols in science and computing: wavelength in physics, eigenvalues in maths, and lambda functions in programming all use it.

Lambda used to label wavelength on a wave

Λ vs ∧ — lambda vs logical AND

One quick disambiguation: uppercase lambda Λ (U+039B) looks a lot like the logical AND sign ∧ (U+2227, also called the “wedge”). They’re different characters with different meanings — Λ is the Greek letter, ∧ is the conjunction operator in logic. Use the one you actually mean, especially in code and formulas.

Quick reference

Symbol	Name	Windows	Mac	HTML	LaTeX	Unicode
λ	Greek small lambda	Alt + 955	Viewer / Greek input	`λ`	`\lambda`	U+03BB
Λ	Greek capital lambda	Alt + 923	Viewer / Greek input	`Λ`	`\Lambda`	U+039B

Type lambda on Windows

Alt codes: hold Alt, type on the numeric keypad (Num Lock on): Alt + 955 → λ, Alt + 923 → Λ. Use a Unicode-aware app (Word, browsers, email).
Word: type 03BB and press Alt + X for λ, or 039B + Alt + X for Λ. In an equation (Alt + =), type \lambda or \Lambda then Space.
Lots of Greek: add the Greek keyboard and switch with Windows + Space.

Type lambda on Mac

Macs have no direct Option shortcut for lambda:

Character Viewer: press Control + Command + Space, search “lambda,” and double-click λ or Λ.
Greek input source: add it under System Settings → Keyboard → Input Sources, or use Unicode Hex Input (Option + 03BB).

Lambda in programming

In code, “lambda” usually means an anonymous function — a short function with no name. The idea comes from lambda calculus, Alonzo Church’s 1930s formal system where λx.x+1 denotes a function. You’ll see it as the lambda keyword in Python (lambda x: x + 1), as arrow functions elsewhere, and as the name of AWS Lambda, the serverless compute service. In source code you normally type the word lambda; the λ character itself appears in lambda-calculus notation and documentation — copy it from above when you need it.

Lambda in HTML & LaTeX

HTML: λ → λ, Λ → Λ; numeric fallbacks λ / Λ (or hex λ / Λ) render the same.
LaTeX (math mode): \lambda for λ, \Lambda for Λ — as in c = \lambda \nu (wavelength) or \det(A - \lambda I) = 0 (eigenvalues).

Type lambda on Linux & phone

Linux: Ctrl + Shift + U, then 03bb (λ) or 039b (Λ), then Enter.
Phone: add a Greek keyboard (iPhone: Settings → General → Keyboard; Android: Gboard languages) and switch with the globe key, or copy λ/Λ from the tool above.

What lambda means

Wavelength (λ) — the distance between wave crests, in physics and optics: λ = c/f, the de Broglie wavelength λ = h/p, the Compton wavelength.
Eigenvalues (λ) — in linear algebra, the scalars in Av = λv and the characteristic equation det(A − λI) = 0.
Lambda calculus & functions (λ) — anonymous functions in computer science, from Church’s lambda calculus.
Decay constant (λ) — the rate of radioactive/exponential decay; half-life = ln 2 / λ.
Rate parameter (λ) — in Poisson and exponential distributions in statistics.
Cosmological constant (Λ) — uppercase lambda in general relativity, the energy density of space (the “Λ” in ΛCDM).
Also — Lagrange multipliers, thermal conductivity, the Lebesgue measure; and culturally, the orange Λ of the Half-Life games.

Troubleshooting

Problem	Fix
Alt + 955 gives the wrong character	Use the numeric keypad with Num Lock on, in a Unicode-aware app.
λ shows as a box ▯	Font lacks the glyph — switch to Segoe UI, Arial or Cambria Math. See symbol showing as a box.
Option + L didn’t work on Mac	There’s no standard Option shortcut for lambda — use the Character Viewer (Control + Command + Space).
I meant logical AND, not Λ	Use ∧ (U+2227), the logical-conjunction sign, not uppercase lambda.
λ looks like an upside-down “y”	That’s the normal shape of lowercase lambda — keep it distinct from y and the Latin “v”.

Recap

Windows → Alt + 955 (λ) / Alt + 923 (Λ); Word: 03BB + Alt + X.
Mac → Character Viewer (Control + Command + Space) — no Option shortcut.
Web → λ / Λ. LaTeX → \lambda / \Lambda.
In code → usually the word lambda; copy the λ character for notation.

Frequently asked questions

What does the lambda symbol mean?

Lambda is the 11th letter of the Greek alphabet, written Λ (uppercase) and λ (lowercase). It represents wavelength in physics, eigenvalues in linear algebra, decay and rate constants in science and statistics, and — in computer science — lambda calculus and anonymous “lambda” functions.

How do I type lambda on Windows?

Hold Alt and type 955 on the numeric keypad for λ, or 923 for Λ, in a Unicode-aware app. In Word, you can also type 03BB (or 039B) and press Alt + X, or use \lambda in an equation. For lots of Greek, add the Greek keyboard layout.

How do I type lambda on a Mac?

Macs have no direct Option shortcut for lambda. Open the Character Viewer with Control + Command + Space, search “lambda,” and insert λ or Λ, or add the Greek input source. You can also use Unicode Hex Input with Option + 03BB.

What is lambda in programming?

In programming, a lambda is an anonymous function — a small function defined without a name. The concept comes from lambda calculus, a formal system created by Alonzo Church in the 1930s. Python uses the lambda keyword, and “AWS Lambda” is a serverless compute service named after the idea.

What does λ mean in physics?

In physics, λ most often means wavelength — the distance between successive crests of a wave — as in λ = c/f. It also denotes the decay constant in radioactive decay and appears in the de Broglie and Compton wavelengths.

What’s the difference between Λ and ∧?

Uppercase lambda Λ (U+039B) is the Greek letter, while ∧ (U+2227) is the logical AND, or conjunction, sign used in logic. They look similar but are different characters with different meanings, so use the one you actually intend — especially in code and formulas.

Written by Igor R.. Tested on Windows 11, macOS, Word and LaTeX. Symbol code points follow the Unicode Standard. Last updated July 2026.