Excel provides a horizontal and vertical ruler in the Page Layout view, and you can use these rulers to measure the width and height of items in a worksheet. By default, the rulers use the measurement units that are specified for your computer's operating system, but you can change the units to inches, centimeters, or millimeters.
Measure the width and height of items in a worksheet
On the View tab, in the Workbook Views group, click Page Layout.
Tip: You can also click the Page Layout button on the status bar.
Use the horizontal and vertical ruler to measure items in the worksheet (such as column width, row height, or the width and height of pages).
Change the ruler units
Click File > Options > Advanced.
In Excel 2007: Click the Microsoft Office Button , click Excel Options, and then click the Advanced category.
Under Display, in the Ruler units box, click the units that you want to use.