Tau Symbol (τ)
The tau symbol τ is Unicode U+03C4, the nineteenth letter of the Greek alphabet. Press Copy to put it on your clipboard, or type it with Alt + 231 on Windows.
- Unicode
U+03C4- HTML
τ- Windows
Alt + 231
How to type the tau symbol (τ)
The quickest way is to press Copy above and paste. To type τ yourself, use the method for your device below.
Windows
- Hold Alt and type 231 on the numeric keypad. This older code (from code page 437) works in Notepad, Word and most desktop apps.
- In Word or Outlook, type 03C4 and press Alt + X. Alt + X converts the hex code before the cursor into the character, and back again.
- Press Win + R, type charmap and press Enter. Tick “Advanced view”, search for Greek Small Letter Tau, then Select and Copy. Character Map is built into every version of Windows.
Mac
- Press Control + Command + Space to open the Character Viewer, search for tau and double-click it.
- With the Unicode Hex Input keyboard enabled (System Settings → Keyboard → Input Sources), hold Option and type 03C4.
Linux & ChromeOS
- Press Ctrl + Shift + U, type 3c4, then press Enter or Space. Works in GTK and IBus apps (GNOME, Firefox, Chrome, LibreOffice) and on ChromeOS.
iPhone & iPad
- Copy τ from this page, then go to Settings → General → Keyboard → Text Replacement and add it with a shortcut such as ;tau. The shortcut then turns into the symbol as you type, in every app.
Android
- Copy τ here, then open Gboard settings → Dictionary → Personal dictionary and add it with a shortcut.
Microsoft Word
- Type 03C4, then press Alt + X.
- Insert → Symbol → More Symbols. Set “from” to Unicode (hex), type 03C4 in “Character code” and click Insert.
Google Docs
- Insert → Special characters, then search for “tau” or draw it in the box.
Excel & Google Sheets
- Enter
=UNICHAR(964)in a cell. It works in Excel 2013 and later and in Google Sheets.
HTML
- Write
τorτin your HTML.
What does τ mean?
Tau (τ, capital Τ) is the nineteenth Greek letter, rhyming with “cow”. Engineers use τ for torque and for the time constant of a circuit, and physicists for the tau lepton and proper time. Some mathematicians promote τ = 2π ≈ 6.283 as the more natural circle constant; June 28 (6/28) is celebrated as Tau Day. On Windows, Alt + 231 types τ.
Common uses
- Mechanics: τ = r × F
- Electronics: an RC circuit’s time constant τ = RC
- Maths: τ = 2π
Tau Symbol codes for HTML, CSS and programming
Every code below produces τ. Use the HTML entity in web pages, the CSS escape in content, and the escape sequence in source code.
| Unicode code point | U+03C4 | |
|---|---|---|
| HTML entity (named) | τ | |
| HTML decimal | τ | |
| HTML hex | τ | |
| CSS content | content: "\3C4"; | |
| JavaScript | "\u03C4" | |
| Python | "\u03C4" | |
| Python (by name) | "\N{GREEK SMALL LETTER TAU}" | |
| Java / C# | "\u03C4" | |
| LaTeX | \tau | |
| UTF-8 bytes | CF 84 | |
| UTF-16 | 03C4 | |
| URL encoded | %CF%84 | |
| Alt code (CP437) | Alt + 231 |
τ vs look-alike characters
These characters look similar to τ but have a different meaning and code. Pasting the wrong one can break search, sorting and screen readers.
| Char | Name | When to use it |
|---|---|---|
TU+0074 | Latin small t, which has an ascender above the crossbar. | |
Greek capital TauU+03A4 | Greek capital Tau (U+03A4), identical to the Latin T. |
Symbols similar to τ
Click to copy, or open a symbol for its codes. See the full greek letters collection.
- Greek Alpha Details
- Greek Beta Details
- Greek Gamma Details
- Greek Epsilon Details
- Greek Zeta Details
- Greek Eta Details
- Greek Theta Details
- Greek Iota Details
- Greek Kappa Details
- Greek Lamda Details
- Greek Mu Details
- Greek Nu Details
- Greek Xi Details
- Greek Omicron Details
- Greek Pi Details
- Greek Rho Details
- Greek Upsilon Details
- Greek Phi Details
- Greek Chi Details
- Greek Psi Details
τ character properties
- Official Unicode name
- GREEK SMALL LETTER TAU
- Also known as
- tau, greek letter tau
- Code point
- U+03C4
- Unicode block
- Greek and Coptic (U+0370–U+03FF)
- General category
- Lowercase letter (Ll)
- Added in
- Unicode 1.1 (1993)
- Plane
- Basic Multilingual Plane (0)
- Emoji
- No, it is a text symbol
Frequently asked questions
What is tau in maths?
Tau (τ) is sometimes used for the circle constant 2π, the ratio of a circle’s circumference to its radius.
What is the alt code for the tau symbol?
On Windows, hold Alt and type 231 on the numeric keypad to get τ. On a laptop without a keypad, copy it from this page or use 03C4 then Alt + X in Word.
How do I type the tau symbol on a Mac?
There is no single Option shortcut for τ on the US layout. Press Control + Command + Space to open the Character Viewer, search for “tau” and double-click it, or copy it from this page.
What is the HTML code for the tau symbol?
Use the named entity τ or the numeric reference τ (hex τ). All three display τ in every browser.
What is the Unicode for the tau symbol?
τ is U+03C4, officially named GREEK SMALL LETTER TAU, in the Greek and Coptic block. It has been part of Unicode since version 1.1 (1993).