How to Write Subscript in HTML and Plain Text

Subscript is a smaller character positioned below the baseline of regular text

Subscript appears in chemical formulas (H2O), mathematical equations, footnote references, and scientific writing. In HTML, you use the  tag to create it. In plain text without formatting, subscript cannot be displayed, so you write the character normally and note it is subscript in context or use a workaround like parentheses or brackets.

The method you choose depends on where you are writing: a web page, a document, an email, or a text-only platform. Each has different tools available.

Key Takeaways

HTML uses the tag: write 2 to display a subscript 2.
Microsoft Word and Google Docs have subscript buttons in the toolbar or under Format menus.
On Mac, press Control + Command + B; on Windows, press Ctrl + =.
Plain text has no subscript formatting, so you must write the number or letter normally and rely on context or use alternatives like H2O or H_2O.
Different platforms (email, social media, messaging apps) support different formatting methods.

Using the tag in HTML

The HTML subscript tag is . Place the opening tag before the character or characters you want to make subscript, and close it with . For example, to write the chemical formula for water, you write: H2O. The browser renders the 2 smaller and positioned below the baseline.

You can subscript a single character or multiple characters. For a mathematical expression like x subscript n, write xn. For a longer subscript like in a chemical compound, write C6H12O6 for glucose. Each subscript portion gets its own pair of tags.

The tag is semantic HTML, meaning it tells the browser and screen readers that the text is subscript, not just visually smaller. This matters for accessibility and for search engines understanding your content.

Creating subscript in Microsoft Word and Google Docs

In Microsoft Word, select the character or characters you want to make subscript. Then either click the subscript button in the toolbar (it looks like a small x with a number below it) or use the keyboard shortcut Ctrl + = (Ctrl and the equals sign). The selected text shrinks and moves below the baseline.

In Google Docs, select the text, then go to Format in the menu bar. Click Text, then Subscript. You can also use the keyboard shortcut Ctrl + , (Ctrl and comma) on Windows or Cmd + , on Mac. The subscript formatting applies when ready.

Both programs let you undo subscript the same way: select the subscript text and press the subscript button or shortcut again. The text returns to normal size and position.

Keyboard shortcuts for subscript on Mac and Windows

On Windows, the universal subscript shortcut in most applications is Ctrl + = (hold Control and press the equals sign). This works in Word, Google Docs, and many other text editors. To remove subscript, press the same shortcut again.

On Mac, the shortcut is Control + Command + B. This works in Word, Google Docs, and many Mac applications. Some older Mac programs use different shortcuts, so check the Format menu if the shortcut does not work.

These shortcuts work only if you have selected the text first. If nothing happens, the process may not support the shortcut, or you may need to use the menu instead.

Subscript in plain text and text-only platforms

Plain text has no formatting at all, so subscript cannot be displayed. If you are writing in a platform that accepts only plain text — such as some email clients, text message apps, or older forums — you have three options: write the character normally and rely on context, use an underscore before the character (H_2O), or use parentheses (H(2)O).

The underscore method (H_2O) is common in chemistry and mathematics because it visually suggests the character is below. The parentheses method (H(2)O) is clearer but less standard. Choose whichever your audience will understand.

Some platforms like Reddit and Discord support markdown formatting, which includes subscript. In Reddit, you use the caret symbol: H~2~O creates subscript. In Discord, subscript is not natively supported, so you must use one of the plain-text workarounds.

Subscript in email and messaging applications

Email clients vary widely in what they support. Gmail, Outlook, and Apple Mail all support subscript if you compose in HTML or rich text mode. Select the text and use the subscript button in the toolbar, or use the keyboard shortcut for your operating system. If you compose in plain text mode, subscript is not available, and you must use a workaround.

Most messaging apps like WhatsApp, Facebook Messenger, and Slack do not support subscript formatting. If you need to send a subscript character in these apps, use the underscore method (H_2O) or write it normally and explain in context. Some apps allow you to paste formatted text from another source, but the formatting often does not carry over.

Subscript versus superscript and when to use each

Subscript is below the baseline; superscript is above it. Subscript is used for chemical formulas (H2O), mathematical subscripts (xn), and footnote references in some styles. Superscript is used for exponents (x2), footnote numbers, and trademark symbols (™).

In HTML, superscript uses the tag instead of . In Word and Google Docs, the superscript button is next to the subscript button, and the keyboard shortcut on Windows is Ctrl + Shift + = instead of Ctrl + =.

Do not confuse the two. A chemical formula written with superscript instead of subscript is incorrect and confusing. Use subscript for anything that belongs below the baseline.

Frequently Asked Questions

Can I make multiple lines of subscript?

You can nest subscripts, but it is rarely necessary. In HTML, you can write 23, though this is unusual. In Word and Google Docs, you select all the text you want subscript and explore the formatting once. Most uses require only a single level of subscript.

Does subscript work in all web browsers?

Yes. The tag is part of standard HTML and works in all modern browsers. It has been supported for decades, so you do not need to worry about compatibility.

What if I need subscript in a PDF?

If you create a PDF from Word or Google Docs, subscript formatting carries over. If you are writing directly in a PDF editor, look for a subscript button in the text formatting toolbar. Most PDF editors like Adobe Acrobat and Preview (on Mac) support subscript.

Can I use subscript in social media posts?

Most social media platforms (Facebook, Twitter, Instagram, TikTok) do not support subscript in posts. If you need to write a chemical formula or mathematical expression, use the underscore method (H_2O) or write it normally. Some platforms may support it if you paste formatted text, but the formatting often does not stick.

Is there a subscript character I can copy and paste?

Yes. Unicode includes subscript digits and some letters. You can search for "subscript 2" online, copy the character, and paste it anywhere. This works in plain text and platforms that do not support formatting tags. However, the character may not display the same way across all devices and fonts, so it is less reliable than using proper formatting.

This guide is for general information only and is not medical, financial, legal, or other professional advice. For decisions specific to your situation, consult a qualified professional. See our Editorial Policy.