Excel's Date & Number Format Codes: The "Secret" Language of Spreadsheets Excel's Date & Number Format Codes: The "Secret" Language of Spreadsheets The **Custom Number Format** feature in Excel allows you to change how a value looks without changing the value itself. This is done by writing "secret" codes that act as display instructions for your data, saving you from complex text formulas. To access this feature, select your cell(s), right-click, choose **Format Cells**, and go to the **Number** tab, then **Custom**. Core Code Syntax: The Four Sections A custom format code can have up to four sections, separated by a semicolon (;). If present, they control how positive, negative, zero, and text values are displayed, in that order: [Positive];[Negative];[Zero];[Text] The Digits: `#` vs. `0` ...