How to Stop Google Docs from Automatically Changing Text to Subscript

The Unwanted Chemistry Equations

Google Docs includes an aggressive auto-formatting engine designed to anticipate what you are typing and format it accordingly. One of its specific behaviors involves recognizing common mathematical or chemical patterns. For example, if you type “H2O”, Docs will often automatically shrink the “2” and drop it below the baseline, converting the plain text into a proper chemical subscript formula (H₂O).

While this is incredibly useful for chemistry students or scientific researchers, it is incredibly frustrating for almost everyone else. If you are writing a technical manual detailing specific model numbers (like “Revision H2O-A”) or dealing with alphanumeric codes that happen to trigger the algorithm, having your characters suddenly shrink and drop out of alignment ruins your document’s formatting. You are forced to manually highlight the tiny number and undo the subscript formatting every single time. To maintain strict control over your text, this automatic conversion should be disabled.

How to Stop Automatic Subscript Formatting

You can turn off this specific text replacement via the Preferences menu.

1. Open a document in Google Docs.
2. Look at the top toolbar and click on Tools.
3. Select Preferences from the dropdown menu.
4. In the Preferences window, click on the Substitutions tab at the top.
5. Scroll down the list of automatic text replacements until you find the specific entries that are causing you trouble (such as the rule that converts H2O to H₂O).
6. Click the checkbox next to the offending rule to remove the checkmark, or click the “X” on the far right to delete the rule entirely.
7. Click the blue OK button to save your changes.

From now on, Google Docs will respect exactly what you type. Alphanumeric codes will remain in a straight line on the baseline, and you will only get subscript formatting when you explicitly apply it via the Format > Text > Subscript menu.