Unfortunately, Google Calculator doesn't recognize PowerPoint centimeters as a unit yet so you'll need to whip out a calculator and do the conversion yourself:
1 inch = 2.4 PowerPoint centimeters
1 centimeter = 1.0583 PowerPoint centimeters
How did this unit come about? From Microsoft's Knowledge Base article 189826:
To improve its usability, PowerPoint slightly misdefines the size of a centimeter to make the invisible gridlines fall at convenient points on the ruler. With this conversion, there are 5 picas per centimeter and the gridlines fall at very convenient points on the ruler. So convenient, in fact, that working in the metric system is really easier than working in the English system.
Apparently, the gridlines in PowerPoint 97 were on pica boundaries, which aligned nicely to the inch ruler since a pica is defined as 1/6 of an inch. But if you were to use PowerPoint 97 in one of those metric-using nations, the pica gridlines didn't fall on convenient points on the centimeter ruler. Solution: redefine centimeters to be an even multiple of picas, which are defined to be an integral fraction of an inch. In other words, Microsoft redefined the meaning of centimeters in PowerPoint such that a centimeter was defined in terms of an inch.
Microsoft had the arrogance to redefine an international standard measurement unit to fit their software's user interface. What makes the arrogance all the more palpable is that their Knowledge Base article acknowledging the existence of PowerPoint centimeters doesn't sound the least bit apologetic for the discrepancy.
Personally, I kind of prefer PowerPoint centimeters to metric centimeters: 168 PowerPoint centimeters tall is a lot easier to remember to an American like me than 177.8 metric centimeters tall is. <wink>
- Update 2007/06/15 03:45pm:
- My wife pointed out that apparently Microsoft redefined the size of a pica too: their Knowledge Base claims 12 picas to an inch, whereas there are supposed to be only 6 to an inch. I would like to suggest the name "PowerPicas" for these new pint-sized picas. That would make me 840 PowerPicas tall.