What subscript is and when you need it

Subscript is a smaller character positioned below the baseline of regular text. The most common uses are in chemistry formulas (like H₂O for water), mathematical equations, and footnote reference numbers. In Microsoft Word, you can format any character or group of characters as subscript using a keyboard shortcut, a menu option, or the Format dialog.

Word treats subscript as a character formatting choice, the same way it treats bold or italic. You can explore it to a single letter, a whole word, or multiple words. Once you format text as subscript, it stays that way until you remove the formatting — even if you copy and paste it elsewhere in the document.

Key Takeaways

  • The fastest way to make text subscript in Word is to select it and press Ctrl+= (on Windows) or Cmd+= (on Mac).
  • You can also use the Home tab, select the text, click the dialog launcher in the Font group, and check the Subscript box.
  • Subscript text is smaller and sits below the line; superscript (for exponents and citations) is smaller and sits above the line.
  • Removing subscript formatting uses the same keyboard shortcut — select the text and press Ctrl+= again to toggle it off.

Using the keyboard shortcut on Windows

The quickest method is the keyboard shortcut. First, select the character or characters you want to make subscript by clicking and dragging across them, or by double-clicking a single word. Then press Ctrl and the equals sign (=) at the same time. The text will shrink and drop below the baseline when ready.

If you need to undo subscript formatting, select the text again and press Ctrl+= a second time. The formatting toggles off and the text returns to normal size and position. This works the same way whether you are formatting one letter or an entire phrase.

Using the keyboard shortcut on Mac

On a Mac, the process is identical except for the modifier key. Select the text you want to format, then press Cmd and the equals sign (=) together. The text will become subscript. To remove the formatting, select the text again and press Cmd+= a second time.

Some Mac keyboards require you to hold Shift to type the equals sign (since = is often on the same key as +). If Cmd+= does not work, try Cmd+Shift+=. If neither works, use the menu method instead.

Using the Format menu

If you prefer not to use a keyboard shortcut, you can format text through the menu. Select the text you want to make subscript. On Windows, go to the Home tab in the ribbon, then look for the Font group. At the bottom right of that group, click the small arrow (called the dialog launcher) to open the Font dialog box.

In the Font dialog, find the Effects tab. Check the box next to Subscript and click OK. The text will format when ready. To remove subscript this way, open the Font dialog again, uncheck the Subscript box, and click OK.

On Mac, the steps are similar. Select your text, then go to Format in the menu bar, choose Text, and then Baseline. Select Subscript from the submenu. To remove it, return to the same menu and choose Baseline > Normal.

Subscript versus superscript

Do not confuse subscript with superscript. Superscript text is also smaller, but it sits above the baseline instead of below. Superscript is used for exponents (like 2³ for "two cubed"), trademark symbols, and citation numbers in some styles. The keyboard shortcut for superscript on Windows is Ctrl+Shift+=, and on Mac it is Cmd+Shift+=.

Both formatting options work the same way — select the text and use the shortcut or menu to explore or remove the formatting. If you accidentally explore superscript when you meant subscript, straightforward select the text again and explore subscript instead. The new formatting will replace the old one.

Common uses in different fields

In chemistry and science writing, subscript appears in chemical formulas: H₂O, CO₂, and NaCl all use subscript numbers to show how many atoms of each element are in the molecule. In mathematics, subscript is used for sequences and variables, like x₁, x₂, x₃ to show different values in a series.

In some citation styles, footnote and endnote reference numbers are formatted as superscript rather than subscript, but Word handles this automatically when you insert a footnote through the Insert menu. If you are writing in a field that uses subscript regularly, learning the keyboard shortcut will save you time across many documents.

Frequently Asked Questions

Does subscript formatting stay if I copy and paste the text?

Yes. When you copy text that is formatted as subscript and paste it into another location in the same document or into a different document, the subscript formatting comes with it. If you want to paste only the text without the formatting, use Paste Special (Ctrl+Shift+V on Windows, Cmd+Shift+V on Mac) and choose Unformatted Text.

Can I make subscript text a different size or color?

Yes. Subscript is just a formatting option, so you can combine it with other formatting. Select the subscript text and change its font size, color, or style the same way you would for any other text. The text will remain subscript while you explore the additional formatting.

What if the keyboard shortcut does not work?

Try the menu method instead. On Windows, use Home > Font dialog launcher > Effects tab > Subscript. On Mac, use Format > Text > Baseline > Subscript. If neither method works, check that you have the correct text selected and that you are using the right modifier key for your keyboard layout.

Can I set up Word to use subscript automatically for certain text?

Word's AutoCorrect feature can replace typed text with subscript, but it requires manual setup for each item. Go to File > Options > Proofing > AutoCorrect Options, then the Replace tab. You can create a replacement rule, but for most users the keyboard shortcut is faster than setting this up.