How to measure fabric......is something I never learned to do until I began buying and selling it.  I once thought it took a mathematician to figure out plain old yardage.  Unfortunately I still do have a hard time so I grab the nearest calculator.   My point is not really to give advice on how to measure yardage but what to expect when you buy it or sell it.  I only learned recently (close to mid-life) that most people are quite good at figuring it out so I generally leave it to the seller when I buy.  If I were to buy 3 yards of fabric,  you'd probably say, "well 3 yards is what you'll get."  That is usually true.  However, I did find out to my embarrassment that 3 yards is exactly 3 yards, not an inch short or long.  Well, long is ok but short.....NOT!  I have sold literally thousands of yards on eBay in the past 9 years and my impression was the same...3=3.  What is so nice about these tidbits on measuring is that most women, (men too!) will usually give you that extra inch or so.  Why?  Well, for the most obvious reason is that all measuring devices may be just a hair different from each other.  So if I am a seamstress sewing a one-of-a-kind wedding dress, it must be EXACTLY what I ask for, therefore I would like to think that the person I buy it from is sending me that extra inch just in case my device is off a fraction from theirs!  In other words, please do not short the fabric, a thousand dollar dress can be ruined by just that very fraction of an inch, just ask any seamstress!  So what I'm saying is that if you are a seller and you sell lots of fabric, please include that tiny inch "just in case" and if you are buying you can expect an extra inch from me. 

One more point on the subject.  If you are selling a table cloth, the same theory applies as well to carpets, rugs, curtains, etc.  Have you ever hung an item on your biggest wall only to find it was just a fraction off center?  It looks positively terrible!  This is the same thing that can happen when the carpet is too long by one inch for the room.   So please ladies and gentlemen, be sure of your measurements, the difference is profound in some cases such as this! 

Keep Sewing!  Keep buying old AND new textiles........It's a great thing and on eBay you can find some of the most fantastic deals in the world!  Good luck!