How to check if a cell is blank in Excel

IF a cell is blank, return something

Compare the cell to an empty string, "". If it is empty, IF returns the second argument, otherwise the third. Here the follow-up column already does this: tasks with no completion date say Chase.

This is the test to use in most formulas, because it treats an empty cell and a formula that returns "" the same way, which is usually what you mean by blank.

ISBLANK and formulas that return ""

D2 looks empty, but it holds a formula that returned "". ISBLANK checks whether a cell has any content at all, and a formula counts as content. So ISBLANK(D2) is FALSE while D2="" is TRUE.

That catches people out when one column is built from another. If you chain a check onto a formula column, use ="" or LEN(D2)=0. Keep ISBLANK for the rare case where you need to know that a cell has truly never been filled in.

Cells that look blank but hold a space

B4 has a single space in it, typed by accident or left by an import. Neither ="" nor ISBLANK sees it as blank. Wrap the cell in TRIM, which removes spaces, and check the length.

Use this version on any data that came from a form, an export or copy and paste.

IF a cell is not blank

Flip the test with <>, which means not equal to. A2<>"" is TRUE when the cell has anything in it. Use it to fill a column only on rows that have data, so the rest of the column stays empty instead of showing zeros or errors.

Check several cells at once

Use OR when any blank cell should trigger the result, and AND when all of them must be filled. Row 5 has a completion date but no owner, so it is flagged.

For a long row, counting is shorter: =IF(COUNTA(A5:C5)<3,"Incomplete","OK"). Note that COUNTA counts formulas returning "" and cells with a space as filled.

Return a blank instead of 0

A formula that points at an empty cell returns 0, not a blank. =C3 shows 0, and a chart or average will treat it as a real zero. Return "" when the source is empty to keep the result empty too.