U+0398 · Greek and Coptic

Greek Capital Letter Theta Θ

Θ is the capital form of theta, the eighth letter of the Greek alphabet. In computer science it expresses a tight bound in asymptotic analysis, as in Θ(n log n). Engineers and physicists use it for temperature, angles, and thermal resistance, and it appears in Greek words such as Θεός (God) and Θεσσαλονίκη (Thessaloniki).

WindowsAlt 233

UnicodeU+0398

HTMLΘ

ΘU+0398

Character codes

Unicode code point	`U+0398`
Decimal	`920`
HTML named entity	`Θ`
HTML (hex)	`Θ`
HTML (decimal)	`Θ`
CSS	`\0398`
JavaScript	`\u0398`
Python	`\u0398`
UTF-8 bytes	`CE 98`
UTF-16	`0398`
URL-encoded	`%CE%98`

Character details

Official name	GREEK CAPITAL LETTER THETA
Unicode block	Greek and Coptic
General category	Uppercase Letter (Lu)
SymbolHero category	Greek Letters
Lowercase	θ Theta (θ)
Emoji	No

How to type Θ

Windows

Hold Alt and type 233 on the numeric keypad (Num Lock on), then release Alt. Alt 233 uses the code page 437.
In Microsoft Word or Outlook: type 0398 then press Alt + X.
Open Character Map (search “Character Map” in Start), tick “Advanced view”, search for “greek capital letter theta”, then Select and Copy.

Mac

Press Control + Command + Space to open the Character Viewer, search “greek capital letter theta”, and double-click the result.
With the Unicode Hex Input keyboard enabled (System Settings → Keyboard → Input Sources), hold Option and type 0398.

iPhone & Android

Tap Copy at the top of this page, then long-press where you want it and choose Paste.

Docs & web

Google Docs: Insert → Special characters, then search “greek capital letter theta” or enter U+0398.
HTML: Θ or Θ
Excel / Google Sheets: =UNICHAR(920)

Examples

Merge sort runs in Θ(n log n) time.
Θεσσαλονίκη
Let Θ be the parameter space.
Θ = 45°

Good to know

Don’t mix it up: It resembles the Cyrillic capital Fita Ѳ (U+0472), a historical letter, and the digit zero with a bar.

Tip: In asymptotic notation, write Θ with a plain letter (not a slashed zero), and pair it with O and Ω for upper and lower bounds.

Display: the character itself is always the same code point, but its shape comes from the font on the device showing it. If you see an empty box, the font lacks this glyph—the text is still correct.

Guides

Greek Alphabet Symbols: Every Letter to Copy and Paste

Similar greek letters

Greek Capital Letter Gamma

Capital Delta (Δ)

Capital Sigma (Σ)

Greek Capital Letter Phi

See all 333 greek letters →

Questions

What is the Unicode for Θ?

It is U+0398 (GREEK CAPITAL LETTER THETA), decimal 920.

Is there a Windows Alt code for it?

Yes: Alt 233 on the numeric keypad.

How do I type it on a Mac?

There is no built-in Option shortcut. Use the Character Viewer (Control + Command + Space) and search “greek capital letter theta”, or copy it from this page.

What is the HTML code?

Use the named entity Θ or the numeric reference Θ.