α
α Alpha Symbol
Alpha (α) is the first Greek letter — the significance level in statistics, an angle in geometry, and the alpha particle in physics.
Also known as: alpha symbol, alpha greek, alpha lowercase, significance level symbol.
Codes
| Symbol | α | |
| Uppercase | Α · U+0391 | |
| Unicode | U+03B1 | |
| HTML entity (named) | α | |
| HTML entity (decimal) | α | |
| HTML entity (hex) | α | |
| CSS | \03B1 | |
| LaTeX | \alpha | |
| Windows Alt code | Alt + 224 |
How to type α (Alpha Symbol)
WindowsAlt + 224
Hold Alt and type 224 on the numeric keypad, then release Alt (or type 03B1 then Alt + X in Word).
Mac⌥ + ⇧ + A
Press Option + Shift + a. (Or use Character Viewer and search “alpha”.)
Microsoft Word03B1, Alt + X
Type 03B1, then press Alt + X to convert it to α.
Google Docs
Insert → Special characters, then search “alpha” or “greek small letter alpha”.
LaTeX\alpha
Use \alpha in math mode (\Alpha is not defined — uppercase alpha is just a Latin A shape, so write A).
Usage
- In statistics, α is the significance level — the probability of a Type I error you are willing to accept. α = 0.05 means you accept a 5% chance of rejecting a true null hypothesis.
- Cronbach's α measures the internal consistency of a scale, and in finance α is the excess return of a portfolio over its benchmark.
- In physics α is the alpha particle (a helium nucleus) and the fine-structure constant; in geometry it is a conventional name for an angle.
- Which one to use: α (U+03B1) is the Greek letter. ∝ (U+221D) is the proportional-to relation, and in many fonts the glyphs are almost indistinguishable — but one is a variable and the other is a relation, and they typeset with different spacing. If you meant “varies as”, you want ∝.