I'm designing a PCB for the first time and I'm using NI's Ultiboard software to do so.
I tried uploading my Gerbers to a few cheap fabrication services, but I've noticed one discrepancy: I don't understand how these services are determining the width and height of my board. I designed my board to be 50.8mm by 52.6288mm - the size of the board outline in my design. These services are all detecting my board as being sized 82mm by 66mm. The height discrepancy is small, but why is the width discrepancy so large?
I suppose that the most general question is this: what can I do to limit or estimate the actual size of a PCB before I upload it to a site to be fabricated?
This is my board as it is being interpreted by one such service: