To fill a column by example in Excel: type an example of the finished value in the first cell next to your data, press Enter, then press Ctrl+E or go to Data > Flash Fill. The feature behind that keystroke is Flash Fill, and Microsoft defines it simply: “Flash Fill automatically fills your data when it senses a pattern.” Microsoft’s two example jobs are pulling first and last names out of a single column, and building full names from a first-name column and a last-name column.
This page covers the feature itself: the worked example, the shortcut, the checkbox that turns it on, and the catch that its output is values rather than formulas. The neighboring jobs have their own pages: how to split cells in Excel for getting one cell’s contents into several by any route, Text to Columns for the wizard that splits on a fixed delimiter, and concatenate in Excel for combining with formulas that recalculate.
How do I use Flash Fill?
Microsoft’s worked example: first names in column A, last names in column B, and column C to be filled with the combined names. One finished row is all Flash Fill needs.
| A | B | C | |
|---|---|---|---|
| 1 | First name | Last name | Full name |
| 2 | Maria | Jones | Maria Jones |
| 3 | Priya | Patel | |
| 4 | Sam | Ortiz |
On Windows, Microsoft’s steps run on their own:
- Enter the full name in C2 and press Enter.
- Begin typing the next name in C3. Once Excel recognizes the pattern, it offers a preview: the rest of the column, already filled with combined names.
- Press Enter to accept the preview.
On a Mac, Microsoft’s steps are shorter and manual: type the full name in C2, press Enter, then go to Data > Flash Fill or press Ctrl+E, and Excel fills the cells below from the pattern in C2. Microsoft’s Mac instructions end there; no preview step is described.
| A | B | C | |
|---|---|---|---|
| 1 | First name | Last name | Full name |
| 2 | Maria | Jones | Maria Jones |
| 3 | Priya | Patel | Priya Patel |
| 4 | Sam | Ortiz | Sam Ortiz |
If no preview shows up on Windows, Microsoft’s first suggestion is that the feature might not be turned on: you can run it anyway with Data > Flash Fill or Ctrl+E, and the enable checkbox is covered in the not-working section below.
What does Ctrl+E do in Excel?
Ctrl+E runs Flash Fill. It is the same keystroke in Microsoft’s Windows and macOS instructions, which print Ctrl+E on both platforms rather than a Command variant for the Mac, and it does the same thing as selecting Data > Flash Fill on the ribbon. Two situations call for it: on a Mac, where you type the example and then run the command, and on Windows, when the automatic preview does not appear and you want the fill without retyping anything.
Does Flash Fill write formulas?
No, and this is the caveat that decides when to use it. The filled cells hold ordinary values: Microsoft’s walkthrough ends with the column filled in with the combined names as text, and that text is all the cells contain. Nothing ties column C back to columns A and B, so if someone corrects a spelling in the source afterwards, the filled column keeps the version Flash Fill wrote. The same trade applies to Text to Columns: fast once, static afterwards.
When the output has to follow the source, use formulas instead. Combining names, addresses, or codes with CONCAT, TEXTJOIN, or the ampersand is covered in concatenate in Excel, and the splitting formulas live in how to split cells in Excel.
Why is Flash Fill not working?
Three things to check, in order: the enable checkbox, the manual run, then giving the preview a second example.
Check that it is enabled (Windows). Microsoft’s enable page warns that “if you’re on a Windows device, you may need to enable this feature before using it”. The path: select File > Options, choose Advanced in the left pane, make sure the Automatically Flash Fill box is checked, and select OK. Microsoft’s final step is to close and restart Excel, so a fill that still refuses after ticking the box may just need the restart. The checkbox is documented for Windows; the Mac instructions carry no enable step.
Run it manually. Select the column you are filling and go to Data > Flash Fill, or press Ctrl+E. Microsoft gives this step even for the case where the feature is already enabled but nothing fills, and on a Mac this is the only route Microsoft describes, not a fallback.
Give it the second example (Windows). The automatic preview is documented as appearing while you type the next entry: the example goes in C2, and the preview arrives once you start typing in C3. One entry with nothing typed below it may not be enough to bring the preview up, so either begin the second row or skip the wait and run the command yourself.
When is Flash Fill the right tool?
Microsoft’s guidance on its split-a-cell page recommends Flash Fill when a text split does not follow one consistent rule, or when you would rather show Excel an example than spell the rule out, and it names both name jobs, separating from one column and combining from two, as the good cases. As a routing table:
- The same delimiter on every row: Text to Columns, which gives you delimiter checkboxes, a preview, and per-column formats.
- A pattern you can demonstrate but not easily specify: Flash Fill, one example and Ctrl+E.
- Output that must stay live: formulas, with the split patterns in how to split cells in Excel and the combining patterns in concatenate in Excel.
Does Flash Fill work in Excel for the web?
Microsoft documents Flash Fill for desktop Excel: the versions listed on its Flash Fill pages run from Excel 2016 up on Windows plus the Mac editions, and no web edition appears on either page. Neither page describes a browser procedure, so do not count on any of the steps above in Excel for the web. For splitting text in the browser, Microsoft points at the TEXTSPLIT function instead, and the combining patterns in concatenate in Excel are formula work in any version.
The short version
- Flash Fill fills a column when Excel recognizes a pattern in the example you type. Put the first result in the cell next to your data, press Enter, then press Ctrl+E or go to Data > Flash Fill.
- On Windows, typing the second entry can bring up a preview of the whole column, and Enter accepts it. On a Mac, you type the example and run the command yourself.
- Not filling? On Windows, tick Automatically Flash Fill under File > Options > Advanced, select OK, then close and restart Excel, and remember the manual run works even when the automatic preview does not appear.
- The output is values, not formulas: the filled column does not follow later edits to the source. The routes that recalculate are in concatenate in Excel and how to split cells in Excel.
- Flash Fill is for patterns you can demonstrate; one fixed delimiter on every row is a job for Text to Columns. Because the fill writes plain values, a wrong guess sits in the column looking just like a right one. Compare the original against the filled copy and every cell the fill wrote lands in the list of changes.
