That's not the size I made it!
 

I just measured my favorite couch quilt.

It is now approximately 61 x 80 inches.

I am fairly sure that my unquilted top was approximately 65 x 85 inches.

So- where did those other inches go?

Some of it was taken up in the quilting - and that was not very dense quilting - some of it is probably additional shrinkage over the years - even though I washed the batting and fabrics before assembling them.

So - if one is using unwashed fabrics, a batting that is expected to shrink (if not washed), and dense quilting - expect that the quilt top one made that is a certain size - will be smaller after it is quilted - and smaller yet after it has been washed.

A lot of times that may or may not matter. But if it does - take into consideration that "shrinkage" happens when the item is quilted - and even washed fabrics seem to shrink a bit more over time.

The blocks in this particular quilt were 10 x 10 when I made the top. They are only 9.5 x 9.5 now. This quilt is probably around 20 years old now, but I was very surprised when I measured the blocks. I even stretched them out!

my shrinkage has come in the form of mattresses :) I made double quilts because we had a double mattress, I think we were about the last couple in the country to switch up to queen! So I ripped a sheet into 5 strips and sewed them on the bottom of the double quilts and started making queen sized ones. Enter new mattress this year. We had to sit the box springs on the floor in order to get into bed :) and the queen quilts are now too short. I've given up on the doubles and run them long ways across the bed and use as duvets.
The one I just finished is 108" long, I'll find out next weekend when I remake the bed if it will need an extender too!

Someone posted an interesting article on shrinkage recently. The author made several of the same quilt under different circumstances (washed/unwashed fabric/ shrunk/unshrunk batting, etc.) and posted pictures of the results. I don't remember the title of the thread, unfortunately.

I haven't noticed that. We still have a double size bed. The quilts I made for years ago it still fit. New ones I make for it fit. We have a tall bed. No climb in or out, butt high.

I made a King for our bed and didn't prewash the fabric. When I washed it it did shrink some but I made it large enough so that it isn't a problem.

I notice a bit of shrinkage in a few quilts for the most part I have always compensated by making my quilts a bit over sized. It is just a habit of mine. I prefer larger than smaller quilts. Over the years on some quilts they settle into being just a bit smaller but for me that's ok.

Maybe this is the video your thinking about? It's by Get It Done Quilts

https://www.youtube.com/watch?v=7f0HCDygUeI

I had the same problem when I went from a double to a queen. I got a frame that was lower to the floor and that solved that problem.

just Get It Done Quilts on YouTube did a study. Don't know if that was the one referenced in the thread but I think she did a good job with comparing unwashed, p rewashed quilt fabric

I look at what the batting shrinkage is, and I adjust my size appropriately, usually by adding another border or making one a bit bigger. For example, if I want a 100” square and shrinkage is 4%, I plan on a quilt 104” before washing. I also like nice long drops on bed quilts, so that gives me some wiggle room.