It is often stated that Micro Four Thirds cameras have a 2.0 focal length multiplier. In other words, a 14mm lens on Micro Four Thirds is said to be equivalent to a 28mm lens on a full-frame camera.
The problem with this comparison is that full-frame has a 3:2 aspect ratio, while Micro Four Thirds has a 4:3 aspect ratio. If you crop one picture or the other so that the two pictures have the same aspect ratio, you will get a different focal length multiplier.
If you crop the full-frame image to 4:3, then the focal length multiplier is 1.85. So a 14mm lens on Micro Four Thirds becomes equivalent to 26mm on full-frame.
If you crop the Micro Four Thirds image to 3:2, then the focal length multiplier is 2.08. So a 14mm lens on Micro Four Thirds becomes equivalent to 29mm on full-frame.