How do I expand all columns in Excel spreadsheet?

I have a spreadsheet with many columns. The columns are all a small standard width. Double-clicking the partition line between columns will expand the column width to encompass the longest string in that column.

Is there a shortcut to perform this operation on every column in the spreadsheet?

Solution 1:

Click where the row and column headers meet, this will select the entire sheet, like so:

Then double-click any one of the column partition lines.

I do this all the time, and it's as quick as you can get.

Solution 2:

I don't know about shortcut. I use menu.
1) Select The Full Spreadsheet
2) Select Format
3) Column
4) Autofit Selection

Solution 3:

Ctrl+A to select all cells, then press Alt+H, O, I.