σ
Sigma in Mathematics
In Mathematics, the Sigma symbol (σ) is commonly used. Learn how to copy and use it in your technical documents.
Unicode
U+03C3
HTML Entity
σ
LaTeX Sequence
\sigma
Primary Field
MathematicsMathematics Application
Lowercase sigma is the standard deviation in statistics (a measure of spread), mechanical stress in engineering, electrical conductivity, and surface charge density in physics. Its capital form Σ is the summation operator.
How to type Sigma (lowercase) (σ)
- Fastest: click σ on the keyboard above — it copies to your clipboard, ready to paste into Word, Google Docs, email or a forum.
- Unicode: the code point is shown in the panel above; on Windows you can also use Alt‑X after the hex code in Word.
- LaTeX: use the command shown above inside math mode.
- Anywhere: because it’s standard Unicode, it keeps its exact form across apps and devices.
Frequently asked questions
What does σ mean in statistics?
Standard deviation — how far values typically fall from the mean. About 68% of a normal distribution lies within ±1σ.
How is σ different from Σ?
Lowercase σ is standard deviation (or stress); capital Σ means ‘sum of’.
Write mathematical and scientific expressions
Need to pair this symbol with other operators?