SailorDumb
by default, 1 column width is 8.43 pixels. Do you mean you need to change 100 columns to 1 pixel each? or 1 column to 100 pixels? Either way, highlight however many columns you want to simultaneously change, right click on the column, the part where the letters are (not the actual cell) and click "column width...". A popup box should appear, and you could type in the amount of pixels. Hit enter.
IXL@XL
Selct the columns to change width, left click on edge of columns (double headed arrow appears and drag edge to the right if you want wider, left if slimmer (read off the width that appears next to cursor (pixels and cm's)
garbo7441
@SailorDumb
While the default column width in Excel is 8.43, that is based on the default font Excel assigns of Arial 10. If you change your font, the column widths will change.
The 8.43 value means that the column will display 8.43 characters of Arial 10, based on the character width of '0'.