No. No it's not. It's button knot to button hole. If you measure the whole collar you will get the wrong size. This is why I really harp on going to a tailor or another professional who knows how to measure.It's worth the trip.
Correct. If you measure your best fitting shirt one inch below the pit whatever that measurement is is the number you want to buy. My wife is still working on fixing the size charts. The BD shirts are finished.I put the old S, M,L sizes up as references. However if you want a nice chest size measure your shirt one inch below the armpit seam. That flat measurement double is your finished size.One the chart the numbers below 37,38,39,40,etc..... are the finished measurements.
This should help everyone as a lot! Here is a picture of measuring a collar flat. button to button hole.
Measure your best fitting shirt like that for your neck size. Please note giving a .25 or .50 is not a lot. For example. The neck on the Large BD is 17 I am 16.5 but I still wear the large BD and the fit is nice.
Now I have the option of a 16.5 neck and a better chest size.
I hope this helps. It should.