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!