How to Disable the Automatic Capitalisation of First Letters in Microsoft Excel

Microsoft Excel includes a built-in AutoCorrect feature that silently monitors your typing and attempts to fix common mistakes. One of its most aggressive behaviours is automatically capitalising the first letter of a word if it thinks you are starting a new sentence within a cell. While helpful for writing paragraphs in Word, this is often disastrous in Excel. If you are entering raw data, complex passwords, scientific notations, or case-sensitive product codes (e.g., “iPhone” or “macOS”), Excel will aggressively change them to “IPhone” and “MacOS.” To maintain the integrity of your exact data entry, you must disable this automated capitalisation.

How to Disable Automatic Capitalisation

This setting is buried deep within the Proofing options. Changing it will apply to all future Excel spreadsheets you edit on your computer.

1. Open Microsoft Excel.
2. Click on the File tab located in the top-left corner of the window.
3. Look at the bottom of the left-hand blue sidebar and click on Options. (You may need to click ‘More…’ first to reveal Options).
4. The “Excel Options” dialogue box will appear. In the left-hand menu pane, click on Proofing.
5. At the very top of the main window, click the large button labelled AutoCorrect Options….
6. A new “AutoCorrect” dialogue box will pop up. Ensure you are on the AutoCorrect tab.
7. Look at the list of checkboxes at the top. Locate the setting labelled Capitalize first letter of sentences.
8. Click the checkbox to uncheck it.
9. Optional: If you frequently type day names in lowercase for specific coding reasons, you may also want to uncheck “Capitalize names of days”.
10. Click OK on the AutoCorrect window, and then click OK on the main Options window.

From now on, Excel will respect your exact keystrokes. If you type a lowercase “i”, it will stay a lowercase “i”, regardless of its position in the cell.