Combine Two Columns Into One
Three routes join two columns, and they differ in what they leave behind — which is the only decision worth making here. A formula keeps a live link, so the joined column collapses into #REF! the moment its sources are deleted; copy it over itself as values before that happens. Flash Fill writes plain text from a single worked example and keeps nothing, which is right for a one-off and wrong for data that will change. Merge & Center is not on the list at all: it fuses cells rather than values, and discards everything except the top-left one.
The formula
=A2&" "&B2 join two cells with a space between them
=A2&", "&B2 any separator you like, in quotes
=TEXTJOIN(" ",TRUE,A2:C2) join three or more columns, skipping blank cells
=CONCAT(A2,B2) the modern replacement for CONCATENATE, no separator added
Ctrl+E Flash Fill: type the first combined value, then press itA worked example
A2 holds "Ada" and B2 holds "Lovelace", with rows 2 to 40 following the same pattern.
=A2&" "&B2
"Ada Lovelace" appears in C2, and double-clicking the fill handle runs it down to row 40. Column C still depends on A and B, so copy C and use Paste Special > Values before deleting the source columns — delete them first and every combined value turns into #REF!.
Which one do I need?
| If you want to… | Use |
|---|---|
| Joining the text of two columns into one | =A2&" "&B2, or =TEXTJOIN(" ",TRUE,A2:C2) once there are more than two |
| Doing it once, without leaving a formula behind | Type the first combined value in C2 and press Ctrl+E — Flash Fill reads the pattern and fills plain text |
| Making two cells into one wide cell for a heading | That is Merge & Center, and it discards everything but the top-left value — never run it over data |
| Splitting one column back out into two | Data > Text to Columns, or Ctrl+E again when the split is obvious from one example |
| Joining first and last name columns specifically | =A2&" "&B2 in reading order, or =B2&", "&A2 for "Lovelace, Ada" |
| Undoing a merge that has already happened | Home > Merge & Center toggles it off, but the values it discarded are gone — Ctrl+Z is the only recovery, and only straight away |
Frequently asked questions
How do I merge two columns without losing data?
Use a formula or Flash Fill rather than the Merge button. =A2&" "&B2 in a third column builds the combined value while both originals stay intact, and Ctrl+E does the same as static text. The Merge & Center button physically joins the cells and keeps only the top-left value, which is the data loss people run into.
Why did my combined column turn into #REF! errors?
The formulas still point at the source columns, so deleting those columns leaves the references with nowhere to go. Select the combined column, copy it, then Paste Special > Values over itself to turn the formulas into plain text. Once the column holds values rather than references, the originals can be deleted safely.
What is the difference between CONCAT, CONCATENATE and TEXTJOIN?
CONCATENATE is the legacy function, kept only so old workbooks keep opening. CONCAT replaced it and accepts whole ranges instead of one argument per cell. TEXTJOIN adds the two things neither of the others has: a separator specified once rather than typed between every argument, and a flag that skips blank cells so you do not end up with doubled spaces.
Does Flash Fill work in Google Sheets?
Not under that name. Sheets offers Smart Fill, which proposes the rest of the column after you type a couple of examples (Ctrl+Shift+Y, or just accept the suggestion when it appears). The formula routes are identical in both programs — the & operator, CONCAT and TEXTJOIN all behave the same way.
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