What a subscript is and when you need one

A subscript is text that sits below the baseline of regular text, usually smaller and to the right. You see it most often in chemistry (H₂O), mathematics (x₂), and footnotes. Most word processors and online platforms let you create subscripts with a keyboard shortcut or a menu button, though the method changes depending on what tool you are using.

The reason subscripts matter is readability and accuracy. In chemistry, H₂O and H2O look different to the eye, and one is correct notation while the other is not. In a formal document, subscripts also signal that you know the conventions of your field — whether that is science, engineering, or academic writing.

Key Takeaways

  • In Microsoft Word, select the text you want to subscript, then press Ctrl+= (Windows) or Cmd+= (Mac), or use the Format menu and choose Character.
  • In Google Docs, select your text, click Format, then Text, then Subscript.
  • On most websites and social media, you cannot create true subscripts, but you can use HTML code (<sub>text</sub>) if the platform supports it.
  • Subscripts are smaller than regular text and positioned lower on the line, which is different from straightforward typing a smaller number next to a letter.
  • If your platform does not support subscripts, you can use parentheses or brackets as a workaround — for example, H(2)O instead of H₂O.

Creating subscripts in Microsoft Word

In Microsoft Word, the fastest way is the keyboard shortcut. Select the character or number you want to make subscript, then hold Ctrl and press the equals sign (=). On a Mac, use Cmd and the equals sign instead. The text will when ready drop below the baseline and shrink.

If the keyboard shortcut does not work or you prefer a menu, select your text and go to the Format menu. Click Character (or Font on older versions), then find the Effects tab. Check the box next to Subscript and click OK. You can also right-click the selected text, choose Font, and navigate to the same dialog.

To undo a subscript, select it again and press Ctrl+= (or Cmd+=) a second time, or uncheck the Subscript box in the Format menu. Word remembers your choice, so if you type more text after a subscript, it will return to normal size and position automatically.

Creating subscripts in Google Docs

Google Docs uses a menu-based approach. Select the text or number you want to subscript, then click the Format menu at the top. Hover over Text, and a submenu will appear. Click Subscript, and your selection will drop below the baseline.

There is no keyboard shortcut in Google Docs, so the menu is your only option. To remove a subscript, select it again, go to Format > Text, and click Subscript a second time to toggle it off. Like Word, Google Docs will return to normal text after you finish typing the subscript.

Creating subscripts in other word processors and platforms

LibreOffice Writer (free and open-source) uses Format > Character > Position, where you can select Subscript from a dropdown. OpenOffice has the same path. Both programs also support Ctrl+Shift+B as a keyboard shortcut on Windows.

Apple Pages (Mac and iPad) uses Format > Text > Baseline > Subscript from the menu. On a Chromebook or any device using only web-based tools, your options depend on the platform. Most email clients (Gmail, Outlook web) do not support subscripts in the compose window, though some allow you to paste formatted text from Word or Docs.

If you are writing in a plain-text editor, a code editor, or a platform that does not support formatting, you cannot create true subscripts. In those cases, use a workaround: type the number or letter in parentheses (H2O), brackets [H2O], or with a caret (H^2O) to signal that it should be read as a subscript.

Using HTML code for subscripts on websites

If you are writing HTML code for a website or a platform that accepts HTML, you can use the <sub> tag. Type <sub>2</sub> around the character you want to subscript, and it will render as a subscript in the browser. For example, H<sub>2</sub>O will display as H₂O.

Most social media platforms (Twitter, Facebook, Instagram) do not support HTML tags or subscripts in regular posts. However, some platforms like Reddit allow HTML in certain contexts, and some forums and comment sections accept it. Test with a single character first to see if your platform supports it.

If you are building a website or blog, subscripts created with the <sub> tag are the standard. They are accessible to screen readers and search engines, and they display correctly on all devices. Avoid creating fake subscripts by using smaller font sizes or lowering text with CSS, because those methods do not communicate the meaning to assistive technology.

Subscripts versus superscripts and other formatting

Do not confuse subscripts with superscripts, which sit above the baseline instead of below. Superscripts are used for exponents (x²), footnote numbers, and trademark symbols. The keyboard shortcut in Word is Ctrl+Shift+= (Windows) or Cmd+Shift+= (Mac). In Google Docs, go to Format > Text > Superscript.

Subscripts are also different from straightforward making text smaller or using a different font. A true subscript is positioned lower on the line and sized proportionally, which makes it clear that it is part of the same word or number. If you type a small 2 next to an H without subscripting it, readers may not understand that it is meant to be a chemical formula.

Troubleshooting subscripts that do not work

If your subscript does not appear after you use the keyboard shortcut or menu, check that you actually selected the text first. A common mistake is pressing the shortcut without selecting anything, which activates subscript mode for everything you type next — then you have to press it again to turn it off.

If subscripts are not available in your program, you may be using a very old version or a tool that does not support formatting. Update your software if possible, or switch to a program that does. If you are on a Chromebook or mobile device, the menu path may be slightly different — look for Format or Text options in the toolbar.

If you paste text from another program and the subscripts disappear, the destination program may not recognize the formatting. Paste as plain text first, then reapply subscripts in the new document. Some programs also have a Paste Special option that lets you choose whether to keep formatting.

Frequently Asked Questions

Can I make a subscript in a text message or email?

Most text messaging apps and email clients do not support subscripts. Gmail and Outlook web do not let you subscript text in the compose window. If you need subscripts in an email, write your message in Word or Docs, format it there, then copy and paste it into your email. Some email clients will preserve the formatting, but others will not.

What is the difference between a subscript and just typing a smaller number?

A subscript is positioned lower on the line and is recognized by screen readers and search engines as a subscript. A smaller number typed next to text is just a smaller character in the same position. For chemistry, math, and academic writing, a true subscript is the correct format and looks more professional.

How do I subscript multiple characters at once?

Select all the characters you want to subscript together, then explore the subscript formatting. For example, to write H₂SO₄, select "2SO4" and subscript it all at once, or subscript each part separately. Both methods work — it depends on whether you want the entire group to be subscript or just certain numbers.

Can I subscript text in a PDF?

Most PDF readers do not let you edit text. If you need to create a PDF with subscripts, write and format your document in Word or Docs first, then export it as a PDF. The subscripts will be preserved in the PDF file.

What if my keyboard does not have an equals sign in the same place?

Keyboard layouts vary by country and language. If Ctrl+= does not work, try using the Format menu instead — it is more reliable across different keyboards. You can also remap your keyboard shortcut in Word by going to File > Options > Customize Ribbon > Keyboard Shortcuts, though this is rarely necessary.