Unfortunately, its not that simple. Each binding manufacturer has its own size chart that you should refer to to see what size boots fit. In fact, there may be differences between models made by the same company. If you are on the border of a range, you may have some leeway based upon your boots (they may be wide, they may be low profile, etc.)
make sure they give you the right binding....sales rep tend to push large sizes or whatever they have to sell better than what fits you best... My story...I discovered years later that i was using a large CArtel, when a medium would have fit better.
2015/16 -3- Kirkwood days
Arbor A-Frame 158 2009-10
Jeremy Jones Hovercraft 156, 2011/12
Subaru WRX 06
Agreed. I would be sure to do your own research on the manufacturers website so that you know before you get to a store what you need. Only deviate from that based upon actual fit (trying them on with the boots you'll use), rather than word of mouth.