Custom formulas in Google Sheets are user-defined formulas created using Apps Script, which can be used to perform complex calculations or automate repetitive tasks that cannot be achieved using built-in formulas. Custom formulas allow you to create and use your functions in your sheets just like any other built-in formulas. These formulas can be tailored to fit specific needs, such as pulling data from multiple sheets, automating data processing and analysis, or integrating with external data sources. Custom formulas can also create dynamic charts and graphs that update automatically as data changes. This powerful tool allows users to extend the functionality of Google Sheets and streamline workflows, making it an essential tool for data-driven businesses and individuals.
Here are some examples of custom formula you can use. You can write advance logics and reuse them across sheets as well.