Zoom In and Out of an Excel Spreadsheet

The standard zoom setting on an Excel spreadsheet (100%) displays the cells about 2 centimetres wide and half a centimetre high, depending on your screen setup.
You can zoom in and out of a spreadsheet with Control + Alt + Plus and Control + Alt + Minus.
The range of zoom with this shortcut is between 10% and 400% (this is equivalent to the mouse-operated zoom slider on the status bar).
You can also choose zoom levels by pressing Alt + W, then Q, which gives a choice of zoom percentages but also lets you zoom in on a selection of cells.