How to write subscript in Word: steps for PC and Mac

This guide outlines how to write subscript in Word documents and when and how to use it, with steps for both PC and Mac.

What is subscript?

Subscript is text that sits slightly below the normal line of writing and is usually smaller than the surrounding text. You will see it most often in science, maths and technical writing.

A familiar example is the chemical formula for water: H₂O. The 2 sits lower than the H and O because it shows that there are two hydrogen atoms. Subscript is also used in formulas, equations, footnote-style notation and some types of technical abbreviations.

Microsoft Word makes subscript fairly easy to add. There are a few different ways to do it, and the exact keyboard shortcut is different on Windows and Mac.

How to write subscript in Word on a PC

The simplest method is to use the Subscript button on the ribbon.

1. Open your Word document and type the text normally. For example, if you want to write H₂O, you can start by typing: H2O
2. Highlight the character you want to turn into subscript. In this example, select only the 2.
3. Go to the Home tab at the top of Word.
4. Look for the Font section of the ribbon. You should see a button showing an X with a small 2 underneath it: X₂.
5. Click the Subscript button. The highlighted 2 will immediately move below the normal text line and become slightly smaller. You should now have: H₂O

To turn subscript off, click the same X₂ button again before continuing to type normally.

How to write subscript in Word using a keyboard shortcut on a PC

If you use subscript regularly, the keyboard shortcut is quicker.

1. Highlight the character or characters you want to change, then press: Ctrl + = (That means holding down the Ctrl key and pressing the equals key.)
2. Press Ctrl + = again when you want to switch subscript off.

You can also turn subscript on before typing. For example:

1. Type H.
2. Press Ctrl + =
3. Type 2.
4. Press Ctrl + = again.
5. Type O.

This produces H₂O without having to go back and select the 2 afterwards.

How to write subscript using the font dialog box on a PC

There is another method that can be useful if you are already changing other font settings. Highlight the text you want to format, then:

1. Go to the Home tab.
2. Find the Font section.
3. Click the small diagonal arrow in the bottom-right corner of that section.
4. The Font dialog box will open.
5. Under Effects, tick Subscript.
6. Click OK.

This is slower than using the ribbon button or shortcut, but it is useful when you are adjusting several font settings at once.

How to write subscript in Word on a Mac

The ribbon method on a Mac is very similar.

1. Type your text normally.
2. Highlight the character you want to make subscript.
3. Click the Home tab.
4. Find the Font section.
5. Click the X₂ Subscript button.

The selected text will move below the normal line. Click the button again when you want to return to ordinary text.

How to write subscript using a keyboard shortcut on a Mac

On a Mac, the shortcut is different from the Windows version. Highlight the text you want to change, then press: Command + =

On many current versions of Word for Mac, this switches subscript on and off. So, to type H₂O directly, you can:

1. Type H.
2. Press Command + =
3. Type 2.
4. Press Command + = again.
5. Type O.

If that shortcut does not work on your particular version of Word, use the X₂ button on the Home tab instead. Word shortcuts can vary slightly between versions and keyboard layouts.

Using the Format menu on a Mac

You can also use Word’s Font settings.

1. Highlight the text.
2. Open the Format menu at the top of the screen.
3. Choose Font.
4. Select Subscript.
5. Click OK.

Again, this takes a little longer, but it is handy if you are already changing the font, size or other formatting.

How to remove subscript

Removing subscript is just as simple. Select the subscript text, then click the X₂ button again. On Windows, you can also press Ctrl + = and on Mac, press Command + = if that shortcut is supported in your version of Word. The text will return to its normal position.

A useful tip when typing formulas

If you are entering a lot of chemical formulas or similar notation, it is usually faster to switch subscript on and off as you type instead of typing the whole formula first and formatting individual numbers afterwards.

For example, to write CO₂: Type CO, turn subscript on, type 2, then turn subscript off. Just remember to switch it off. Otherwise, everything you type afterwards will continue appearing as subscript.

Subscript versus superscript

Subscript and superscript are easy to confuse. Subscript sits below the normal text line: H₂O. Superscript sits above it: x²

Superscript is commonly used for powers, such as squared or cubed numbers, while subscript is common in chemical formulas and technical notation.

In Word, the buttons sit close together. Subscript is shown as X₂, while superscript is shown as X². If your number suddenly appears above the line instead of below it, you have probably clicked the superscript button by mistake.

For occasional use, the X₂ button on the Home tab is the easiest method. If you regularly work with scientific or technical documents, learning the keyboard shortcut will save quite a bit of time.