Quickly resize a column to fit contents in Excel. You may have data in a cell that is much shorter than, or too long to fit in, the default width of a column. Instead of trying to manually adjust the width of the column to get the right size, double-click the boundary between two column headers (e.g., the line between the A and the B for the first and second columns), and the column size for the column to the left will be perfectly sized to accommodate the cell with the longest text. Easy.