Omega

The omega symbol is Ω in capitals and ω in lowercase. Tap one to copy it, then see the codes, how to type omega, what each form means in physics, electronics and computer science, and why the ohm sign differs.

By Maya Chen, lettering designer and type educator · Checked by Jordan Hale · October 2026 · How we review content

Copy omega

One tap copies one character. Each form below has its own code point.

Key facts

Omega is the 24th and last letter of the Greek alphabet, with a numeral value of 800; capital Ω is U+03A9 and lowercase ω is U+03C9.
The ohm sign Ω (U+2126) is a separate character that Unicode normalises to Greek capital omega, so the Greek letter is the one to use.
In physics, lowercase ω is angular frequency in radians per second (ω = 2πf), and capital Ω can be a solid angle in steradians.
Big-Omega Ω(n) in computer science is an asymptotic lower bound on growth, written with Greek omega and not with Latin O.
As the last letter, omega means "the end", and "Alpha and Omega" is a title of Christ in the Book of Revelation.

Codes for every form

Unicode names and code points for each form, with the escapes you need in HTML, CSS, JavaScript and LaTeX.

Omega: Unicode name, code point, decimal value, HTML entities, CSS and JavaScript escapes, and LaTeX command for each form
Form	Unicode name	Code point	Decimal	HTML	CSS / JavaScript	LaTeX
omega, capital	GREEK CAPITAL LETTER OMEGA	U+03A9	937	Ω Ω	\03A9 / \u03A9	\Omega
omega, lowercase	GREEK SMALL LETTER OMEGA	U+03C9	969	ω ω	\03C9 / \u03C9	\omega

How to type omega

The quick methods for this letter. Step-by-step instructions for each system, and what we have and have not tested, are on how to type Greek letters.

Ways to type omega
Method	What to do
Copy and paste	Use the buttons at the top of this page. Pasted text is plain Unicode.
Word on Windows	Type the code, then press Alt+X: `03A9` for Ω; `03C9` for ω. Windows steps.
Excel and Google Sheets	`=UNICHAR(937)` for Ω; `=UNICHAR(969)` for ω. Office steps.
Windows Alt code	Hold Alt and type on the numeric keypad: `234` gives Ω. From the old code page 437 table; not tested by us on a live Windows machine.
Mac Option key	On a US layout: `Option+Z` gives Ω. Layouts differ by country, and we have not tested every macOS version. Mac steps.
Phone	Add a Greek keyboard: iPhone and iPad or Android.
Web page or LaTeX	`Ω`, `\Omega` for Ω; `ω`, `\omega` for ω. LaTeX commands work in math mode.

These are separate characters, so each has its own code point. Copy the one that matches the job.

How to say omega

Omega pronunciation in English, modern Greek and classical Greek
Reading	Value
English (maths and science)	oh-MEG-uh or oh-MAY-guh, /oʊˈmɛɡə/ or /oʊˈmeɪɡə/
Modern Greek	/o/. The modern Greek name is ωμέγα (oméga).
Classical Greek (reconstructed)	/ɔː/, a long open-mid "o"

English speakers use several stresses, such as oh-MEG-uh in the US and OH-mig-uh or oh-MEE-guh in the UK. In ancient Greek, omega was a long open o, different from the short omicron. In modern Greek the two letters sound the same, /o/. The name means "big o" in the later form ō méga, according to Wikipedia. See the pronunciation page for the whole alphabet.

What omega means, field by field

"Standard" marks a definition or notation that is fixed, such as an SI unit or a named function. "Convention" marks common practice that varies by author, so check the definitions in your own text. The same letter often means different things in different fields; the full table for every letter is on Greek letters in math and science.

Electronicssymbol ΩStandard
The ohm, the SI unit of electrical resistance. Values are written with a space and a prefix, such as 4.7 kΩ or 10 MΩ.
Physicssymbol ωStandard
Angular frequency or angular velocity, in radians per second. It follows from the frequency f as ω = 2πf, so one cycle per second is about 6.28 rad/s.
Physicssymbol ΩStandard
Solid angle, measured in steradians. A full sphere is 4π steradians.
Computer sciencesymbol Ω(n), ω(n)Standard
Big-Omega is an asymptotic lower bound on growth, the counterpart of big-O. Little-omega means strictly faster growth. The big letter is Greek omega, not Latin O or omicron.
Probabilitysymbol ΩConvention
The sample space: the set of all possible outcomes of an experiment, so for a die Ω = {1, 2, 3, 4, 5, 6}.
Mathematicssymbol ωConvention
A primitive cube root of unity, ω = e^(2πi/3), satisfying 1 + ω + ω² = 0. Differential-form texts also use ω for a form.
Cosmologysymbol ΩConvention
Density parameters such as Ω_m (matter) express the density as a fraction of the critical density. They are written with subscripts.
Culture and religionsymbol ΩStandard
Omega is the last letter of the Greek alphabet, so it means "the end". "Alpha and Omega" is a title of Christ in the Book of Revelation, and the pair is a Christian symbol.

Lookalikes and common mistakes

The ohm sign is a different character
The ohm sign Ω is U+2126 OHM SIGN, and Greek capital omega is U+03A9. They look identical and normalise to the same character, so it rarely matters on screen, but searches and mixed-source text can hold either. Use U+03A9, which keyboards and fonts produce.
ω is not w
Lowercase omega has the shape of a rounded w and is often read as one in a hurry. Text that uses a Latin w where ω is meant will not match a Greek search, and screen readers read it as a w.
℧ is not the ohm
The inverted ohm sign ℧ (U+2127) stood for the mho, the unit of conductance, which the SI renamed the siemens (S). Old textbooks and circuit diagrams still show it, but it does not mean ohm.
Big-O is not omicron or omega
In growth-rate notation, big-O uses the Latin letter O (U+004F), and big-Omega uses Ω (U+03A9). Greek omicron Ο looks like Latin O but is a different character, so copying it into a formula breaks searches.
ω and ϖ are both used for angular frequency
Wikipedia notes that the variant pi ϖ is used for the angular frequency of waves in fluid dynamics, because ω is taken. At small sizes ϖ looks like ω with a bar, so check which symbol a source means.

Where does the omega symbol come from?

Omega is the 24th and last letter of the Greek alphabet, with a numeral value of 800. Its original name was ō. It was later changed to ō méga, “big o”, to distinguish it from omicron, “small o”, because both letters had come to be pronounced alike. In modern Greek the name has fused into ωμέγα. That history is in the Wikipedia article on omega.

Because it is the last letter, omega means “the end” in English. In the Book of Revelation, “I am the Alpha and the Omega” is a title of Christ, and the pair is used as a Christian symbol, often with the cross or the Chi Rho. If you are choosing a letter for a design or tattoo, that is the association most readers will bring. The tattoo guide covers spelling and fonts.

What do Ω and ω mean in a formula?

Capital and lowercase omega rarely mean the same thing. A capital Ω after a number is a unit (resistance), and capital Ω alone in probability is a set. Lowercase ω with a subscript or without is a rate: how fast something turns. The sample-space and ohm meanings never meet because probability does not carry units.

If a formula in electronics has both, it will usually look like ω = 2πf for the angular frequency of an AC supply and Z = R + jωL for impedance in ohms. Reading ω as “how fast the signal turns” and Ω as “the unit” keeps them straight.

Why is the ohm sign not the same as omega?

Older documents often carry the ohm sign (U+2126) and the micro sign (U+00B5), characters kept for compatibility with older character sets. Unicode treats the ohm sign as canonically equivalent to omega, so a normalising tool folds it for you. If you are writing now, type the Greek letter. The Unicode page lists the other compatibility pairs, and the science symbols page shows them next to the units they belong to.

How do you write Ω and ω in code and markup?

In HTML, Ω and ω are named entities, and Ω and ω the numeric forms. In CSS, the escapes are \03A9 and \03C9. In LaTeX math, \Omega and \omega give the two forms. For the unit in a LaTeX document, the siunitx package has \ohm.

Sources

These sources back the facts on this omega symbol page. Each field gives omega its own meanings, so check which one your text intends.

Wikipedia, Omega (name, pronunciation, uses)
Wikipedia, Alpha and Omega (the Christian symbol and the Book of Revelation)
BIPM, The International System of Units (SI Brochure) (ohm, siemens)
Unicode Greek and Coptic code chart (PDF)
Alt codes and Option-key shortcuts follow the code page 437 and Mac Roman tables; we have not tested them on live systems.

Frequently asked questions

What does the omega symbol mean?

Capital Ω is the ohm in electronics, a solid angle in physics, the sample space in probability and big-Omega in computer science. Lowercase ω is angular frequency in physics. As a letter it is the last of the Greek alphabet, so it also means "the end" in phrases such as alpha and omega.

Why does omega look like a w?

The lowercase shape ω is rounded and happens to resemble a Latin w. The sound is an "o", not a "w". Omega and omicron used to be different vowels, a long and a short o, and the name ō méga means "big o" to separate it from the "small o" omicron, according to Wikipedia.

What does "Alpha and Omega" mean?

Alpha and omega are the first and last letters of the Greek alphabet, so the phrase means beginning and end. In the Book of Revelation, "I am the Alpha and the Omega" is a title of Christ, and the pair is used as a Christian symbol, often with the cross or the Chi Rho, according to Wikipedia.

Where is omega used in electronics and computer science?

In electronics, Ω is the ohm, the SI unit of resistance, written with a space and a prefix such as 4.7 kΩ or 10 MΩ. In computer science, Big-Omega Ω(n) is an asymptotic lower bound on growth, the counterpart of big-O, and little-omega ω(n) means strictly faster growth.

How do I type the omega symbol (Ω or ω)?

On a US Mac layout, Option+Z types Ω. On Windows, hold Alt and type 234 on the numeric keypad for Ω, or in Word type 03A9 and press Alt+X (03C9 for ω). In Excel or Sheets, =UNICHAR(937) returns Ω and =UNICHAR(969) returns ω. The how-to page covers phones and untested steps.

How do I write the omega symbol in HTML and LaTeX?

In HTML, use Ω and ω or the numeric forms Ω and ω. In CSS, the escapes are \03A9 and \03C9. In LaTeX math, \Omega and \omega give the two forms, and for the ohm unit in a LaTeX document the siunitx package has \ohm.

Is the ohm symbol the same as omega?

Visually yes, in code no. The ohm sign (Ω) is U+2126 and capital omega is U+03A9. Unicode treats the ohm sign as equivalent to omega and folds it into U+03A9 when text is normalised. The Greek letter is the one to use, and the ohm sign is mainly something you will meet in old documents.

What is the difference between ω and ϖ?

ω (U+03C9) is lowercase omega, the standard symbol for angular frequency. ϖ (U+03D6) is a variant of lowercase pi that resembles ω with a bar and has its own uses, for example for the angular frequency of surface waves, where ω is already in use. They are not interchangeable.

Is the big Ω in computer science a Latin O?

No. Big-Omega is Greek capital omega (U+03A9), not Latin O or omicron. A Latin O would read as big-O, which is the upper bound, while Ω is the lower bound. Copy Ω from the buttons above so your notes carry the right character, and do not swap in a lookalike.