What Does An Ohm Symbol Look Like? | Shape, Fonts, Code

If you’re staring at a resistor value or an app screen and asking what the ohm symbol looks like, you’re looking for the uppercase Greek omega, drawn like a rounded arch with its base open. In print it sits upright, not italic, and it pairs with numbers as the unit for electrical resistance.

Ohm Symbol At A Glance

Here’s a fast reference for the glyph, codes, and common ways to enter it in text or code.

Where You Need It	Looks Like	Code Or Entry
Plain text (standard)	Ω	Unicode U+03A9
Legacy ohm sign (avoid)	Ω	Unicode U+2126 (maps to U+03A9)
HTML	Ω	Ω or Ω
LaTeX	Ω	\\Omega
Windows	Ω	Alt+234 (numeric keypad)
macOS	Ω	Option+Z
Word/Office	Ω	Insert > Symbol > Greek

For unit styling, the SI uses an upright roman symbol and a thin space between the number and the unit: write 10 Ω, not 10Ω. You can read the guidance in the NIST SI checklist.

What Does The Ohm Symbol Look Like In Fonts And Code?

Across fonts the outline stays the same idea: an open-bottomed omega. Some fonts draw short “feet” at the ends, others keep a smooth curve. In body text it sits upright because unit symbols are set in roman type. In equations you might see a slanted omega for a variable, but that’s the letter, not the unit.

Shape Notes You Can Trust

• Open base. The stroke curves down on both sides and does not close at the bottom.
• Even stroke. In most sans or slab fonts, the weight matches nearby letters.
• Legible at small sizes. The arch stays wide enough that it doesn’t read as a U.

SI Style Basics For Ω

Write the unit in lower-case letters (“ohm” in text) and use the capital symbol “Ω” with numbers. Keep a space between the value and the symbol, use a non-breaking space on the web to keep them together, and never add a period. Samples:

5 Ω
2.2 kΩ
47 MΩ

Do not pluralize the symbol and avoid italics for the unit. These habits keep lab notes, datasheets, and posts consistent with SI practice.

Ohm Sign Vs Greek Omega (U+2126 Vs U+03A9)

Unicode keeps two code points that show the same glyph. The standard code for the unit is the Greek capital letter omega, U+03A9. There is also a legacy “OHM SIGN,” U+2126. Modern text engines treat U+2126 as a compatibility character that maps to U+03A9. In web pages and apps, prefer U+03A9 or the HTML entity Ω. The official Unicode code chart for U+03A9 points to U+2126 as a related symbol.

Why Two Codes Exist

Older encodings once reserved special slots for unit signs. When Unicode merged many sources, it carried over a few duplicates and marked them to decompose to the regular letter. That is why searches, sorting, and normalization can treat both as the same symbol in practice.

Common Places You’ll See Ω

Anywhere resistance is written next to a number, Ω shows up. Packaging, test screens, and circuit notes all rely on it. You’ll also meet Ω in spec sheets for headphones, speakers, and sensors. Resistor networks may mix Ω with prefixes like k and M to avoid long strings of zeros.

Resistor Values And Labels

Printed parts often drop the decimal point and swap in a letter to keep the value unambiguous: 2K2 means 2.2 kΩ, and 5R6 means 5.6 Ω. Panel labels, app UIs, and CAD footprints usually stick with the plain form like 10 kΩ or 47 Ω.

Not The Resistor Schematic Symbol

Don’t confuse the unit mark with the zig-zag component symbol or the rectangle symbol used in some regions. The Ω sits with the number; the shape on the line is the part.

How To Type Or Insert Ω On Your Devices

Pick the method that matches your setup. Each one yields the same U+03A9 character.

Desktop And Laptop

• Windows: Hold Alt and type 234 on the numeric keypad. Or use Windows Character Map, or the “Emoji & Symbols” panel in many apps.
• macOS: Press Option+Z. You can also open the Character Viewer and search for “omega.”
• Linux: With a Compose key: Compose, then O, then M. Many editors also accept Ctrl+Shift+U then 03a9 then Enter.

Web, Apps, And Code

• HTML: Type Ω or Ω. Avoid Ω since it maps to the legacy sign.
• LaTeX: Use \\Omega for the capital form; pair with \\si or \\SI if you use siunitx.
• Markdown: Paste Ω directly, or use the HTML entity if needed.

Phones And Tablets

• iOS/iPadOS: Add the Greek keyboard in Settings, then tap Ω. Or copy from a notes snippet and keep it on the clipboard manager.
• Android: Many keyboards include a Greek layout you can enable. You can also paste the character from a saved text shortcut.

Quick Typing Cheatsheet

Bookmark these entries if you switch platforms.

Platform	Shortcut Or Path	Extra Notes
Windows	Alt+234	Numeric keypad required
macOS	Option+Z	Works with the U.S. layout
Linux	Ctrl+Shift+U 03A9	Then press Enter
HTML	Ω or Ω	Prefer Ω
LaTeX	\\Omega	Use roman for units
Word/Docs	Insert > Symbol	Pick Greek, then Ω

Design Tips For Clear Ω In Images And Logos

When you set Ω in a diagram or a banner, pick a font that keeps the arch open at small sizes. Test light and bold weights to match nearby text. In unit labels keep the symbol upright. If your layout tool slants all math symbols by default, override it for Ω in labels.

Spacing And Alignment

Keep a hairline space between a number and Ω so the pair breathes and stays readable. On the web, use   to prevent a line break: 220 Ω. In vector tools, set kerning to metrics and check that the gap matches other units on the same line.

Export And Accessibility

When you save charts or schematics to PNG or SVG, write Ω as text instead of flattening it into a raster. That keeps it crisp and lets screen readers announce values in the source HTML. In alt text, write the value in plain words, such as “speaker, 8 ohms.”

Common Confusions And Fixes

• W vs Ω: W is watt, a power unit. Use Ω for resistance.
• Ω vs Ω: Ω is a legacy sign. Use the regular omega code point for new content.
• ω vs Ω: The lowercase letter is common in math; the unit uses the capital form.

Practical Wrap-Up For Everyday Writing

• Use Ω (U+03A9). Avoid Ω (U+2126) in new content.
• Keep a space: write 10 Ω, 2.2 kΩ, 47 MΩ.
• Set the unit upright; save italics for variables.
• In HTML, prefer Ω or the literal character.

If your reader needs to spot resistance fast, a clean, upright Ω placed right next to the value does the job every time.

Coding Snippets You Can Reuse

Dropping Ω into a layout is easy once you save a few patterns. Here are short, copy-ready blocks that keep spacing tidy and glyphs consistent across browsers.

HTML: Clean Unit Pairs

<!-- Non-breaking space keeps value and unit together -->
<span>10&nbsp;Ω</span>
<span>2.2&nbsp;kΩ</span>
<span>47&nbsp;MΩ</span>

CSS: Fallback Stack For Clear Ω

body { font-family: "Inter", "Segoe UI", "Roboto", "Helvetica Neue", Arial, sans-serif; }
.measure { white-space: nowrap; }

The stack above covers common systems while keeping the omega shape open and readable. The .measure class prevents awkward wraps in tight columns.

JavaScript: Insert Ω Without Entities

// Append \u03A9 directly
const span = document.createElement('span');
span.textContent = `220\u00A0\u03A9`; // 220 Ω
document.body.appendChild(span);

How Fonts Draw Ω

Typeface choice changes the mood, but the silhouette stays clear. In a friendly rounded sans such as Roboto, Ω looks smooth and wide. In a crisp neo-grotesque such as Arial, the arch is tighter. In a slab or serif body face, small wedge-like endings may show at the tips. Monospace families often draw a narrower form to fit the fixed cell width.

For UI labels, pick a family that matches your system default so the symbol blends with the rest of the text.

Whatever the style, keep the unit upright next to the value. If an equation editor slants Greek letters by default, set a character style that forces an upright omega for units while letting variables slant inside formulas. That keeps unit labels and math variables easy to tell apart at a glance.

Normalization And Search Tips

Text pipelines that mix sources sometimes contain both Ω and Ω. If your search or filter rules miss matches, run Unicode normalization on input before indexing. The legacy sign decomposes to the regular omega, so normalized text collapses duplicated forms. That improves copy-paste from old files.

When you lint content, scan for missing spaces in unit pairs and for stray italics on symbols.

Unit Prefixes That Pair With Ω

Engineers and makers write a wide range of values with Ω. The most common prefixes are k (kilo, 10³) and M (mega, 10⁶). Low-value shunts and sense resistors may appear in mΩ (milli-ohm) or μΩ (micro-ohm). Keep the prefix tight to the symbol and the space tight to the number:

0.25 Ω
15 Ω
2.2 kΩ
1 MΩ
75 mΩ

On parts and silkscreens, the RKM code avoids dots by swapping the prefix or the letter R into the number. That is why you’ll see 4R7 on a tiny chip package instead of “4.7 Ω,” and 1M0 instead of “1.0 MΩ.” Both forms read fine in text; pick one style and keep it consistent across documents.