Height Of String When Width Is Set

I am working on a report in Excel and there's potential for quite large amounts of text easily over-running a merged sell of maximum row height size. I therefore want to be able to merge the right amount of rows to make the text fit cleanly.My idea was to try and find the height of a string when limiting it's width - essentially placing a piece of text into some kind of container, making that container fit to size (with a set width limit, in this case 640 pixels), and measuring the height of that container. With the height of the said container, I could then work out the amount of standard sized excel rows I want to merge.I tried to use a label but there's no way to set only the vertical element to be autosize.