How to Write Subscript in Microsoft Word (Every Method Explained)

Subscript text sits slightly below the normal line of text and appears smaller — you see it in chemical formulas like H₂O, mathematical notation like x₂, and footnote references. Microsoft Word has several ways to apply it, and which method works best depends on how often you need it, what version of Word you're running, and whether you're working with a mouse, keyboard, or touch interface.

What Subscript Actually Does in Word

When you apply subscript formatting in Word, the selected text drops below the baseline and reduces in size — typically around 68% of the surrounding font size. It's purely a formatting property, not a different character. This matters because it means subscript can be applied to any text, removed just as easily, and it travels with the document when shared. It's separate from Unicode subscript characters (like ₂ or ₃), which are actual characters rather than formatted text.

Method 1: The Keyboard Shortcut ⌨️

The fastest way to apply subscript in Word is the keyboard shortcut:

Windows:Ctrl + =

Mac:Cmd + =

You can use this two ways:

• Before typing: Press the shortcut, type your subscript text, then press the shortcut again to turn it off.
• After typing: Select the text you've already typed, then press the shortcut.

This shortcut works across essentially all modern versions of Word — Word 2013, 2016, 2019, Word for Microsoft 365, and Word for Mac. It's the method worth memorizing if you regularly work with scientific or mathematical content.

Method 2: The Ribbon Button

If you prefer clicking, the subscript button lives in the Home tab of the ribbon:

1. Select the text you want to format (or position your cursor where you'll type).
2. Go to Home → Font group.
3. Click the X₂ button (subscript icon).

The button toggles on and off, so clicking it again removes the formatting. You'll see the X₂ icon sitting next to the superscript button (X²), which raises text above the line instead.

This method is the most visible and requires no memorization, making it practical for occasional use or for users who aren't comfortable with keyboard shortcuts.

Method 3: The Font Dialog Box

For more control — or if you want to apply subscript alongside other formatting changes at the same time — the Font dialog box gives you everything in one place:

1. Select your text.
2. Press Ctrl + D (Windows) or Cmd + D (Mac) to open the Font dialog, or right-click the selected text and choose Font.
3. Under Effects, check the Subscript checkbox.
4. Click OK.

This method is particularly useful when you're also adjusting font size, spacing, or character color in the same step.

Method 4: AutoCorrect and AutoFormat for Repeated Subscripts

If you're writing documents that repeatedly use the same subscript sequences — chemical formulas being the most common example — Word's AutoCorrect feature can handle it automatically:

1. Go to File → Options → Proofing → AutoCorrect Options (Windows) or Word → Preferences → AutoCorrect (Mac).
2. In the Replace field, type a shorthand (e.g., h2o).
3. In the With field, type the formatted version with subscript already applied.
4. Click Add.

This takes a few minutes to set up but pays off in long documents. The trade-off is that AutoCorrect entries are stored locally, so they won't carry over to a different machine automatically.

Subscript in Word Online vs. Desktop Word

The method available to you changes depending on your platform:

Word Online — the free browser-based version — supports subscript through the ribbon only. You'll find it under Home → Font group, though the interface is more compact than the desktop version. The keyboard shortcut does not work in Word Online in most browsers.

Word on mobile devices offers subscript through a simplified font formatting menu, but access varies by device and app version. On smaller screens, it may be nested under a Format or Font option rather than visible immediately.

Removing Subscript Formatting

Removing subscript uses the same controls as applying it:

• Press Ctrl + = (or Cmd + =) with the subscript text selected.
• Click the X₂ button in the ribbon again.
• Open the Font dialog and uncheck Subscript.

You can also clear all formatting from selected text using Ctrl + Space (Windows) or by clicking Clear All Formatting in the Home tab — though this removes all font formatting, not just subscript.

When Subscript Formatting vs. Unicode Characters Matters 🔬

There's a distinction worth knowing: typed subscript formatting and Unicode subscript characters look similar on screen but behave differently. Unicode subscript digits (₀₁₂₃₄₅₆₇₈₉) are actual characters — they can be copied into plain-text fields, emails, or web forms and retain their appearance without any special formatting. Subscript formatting in Word only renders correctly inside environments that support rich text.

For documents staying inside Word or being exported to PDF, formatted subscript is reliable and gives you more flexibility (it works with any letter or symbol, not just digits). For content that will be copied into plain-text environments, Unicode subscript characters may be more portable — though the available character set is limited.

The right approach depends on where your document ends up and what characters you need to subscript — and that's a variable only your specific workflow can answer.