The hidden engine behind the fill handle

When you use the fill handle—the tiny green square in the corner of a cell—Excel references its four default maps: the days of the week and the months of the year (both short and long form).

A custom list, by contrast, is a user-defined sequence that tells Excel, “When I type ‘North,’ the next items are ‘South,’ ‘East,’ and ‘West.'” Once saved, the list becomes part of Excel’s settings on your computer. Crucially, while the list itself lives on your PC, the results are persistent: if you sort a table using a custom list and share the workbook, the order stays the same, even if your coworker doesn’t have that list saved.

Where to find Custom Lists in Excel

If you’ve never even seen the Custom Lists feature before, you’re not alone. Microsoft tucked it deep inside Excel’s Advanced options, probably to prevent casual users from accidentally altering the global logic of how Excel handles data. But once you know where to find it (and how to use it), it’ll likely be something you’ll revisit often.

To find Custom Lists:

1. Open Excel and click the File tab.
2. Click Options at the bottom of the sidebar.
3. In the Excel Options window, open the Advanced tab.
4. Scroll almost to the bottom to the General section and click Edit Custom Lists.

Create your first custom list in Excel

In the Custom Lists dialog, you’ll see the four default lists I mentioned earlier. To add your own, you just have to provide the sequence. It’s really useful for short lists you use daily, like project statuses or clothing sizes.

1. Select NEW LIST in the box on the left.
2. Click into the box on the right, and type your entries in your preferred order (such as Small, Medium, Large), pressing Enter after each one.
3. When you’re done, click Add, and your new list will appear as a custom list on the left.
4. Click OK to close the dialog box.