About 6 calories each or so (if you mean M&M the chocolate candy). If you meant millimeter, there is no relationship between calories and millimeters.
260 calories
According to one online resource, one m&m has about 4.5 calories, 0.2g fat and 0.6g carbs.
There are 203 calories in 203 calories.
153 mm
180 mm
100 mm
6450 mm
135 mm.
304.8 mm
8500 mm
3,000 mm
760 mm