Thank you Jan for the graphics. They are so help

Me too. Recently, I've started using a little back art - or at least I try to use up some of the left-over blocks and assorted fabrics from the projects to supplement the planned backing fabric. Then it doesn't look like I messed up should I miscalculate and have to add more.

I place the quilt top on my design wall then begin to place the backing on top remembering to leavie enough for a longarm quilter. I too have made mistakes and here is my most recent one. I had two extras fabric squares left over so I attached a border around each one (they are NEVER printed square) to sew into the backing. But on the background piece that is below and above the block, I was short over an inch!! So I just insert a long red strip that is going down on the left block and going up on the right block. Thank goodness that problem was resolved. It probably looks a little bit more interesting than what I had originally planned. So don't EVER feel like you are the ONLY one making mistakes !!! Hang in there!!! Hopefully there will always be an easy fix for any error.

I fold the top in half vertically and measure on a tape that is taped to a table. If it is 48" X 2 = 96in add extra 6inches so the vertical measurement is 102"

I do the same horizontally. Lets say that the end measurement is 86" I do not measure the backing to the top
After I have found the measurements I will be sure that the backing measures the 102" x 86"

I always measure to an affixed tape. I worked at a quilt store and that is how we would figure out the amount of fabric to buy.

Jan thank you for your graphics. Love the tech era we live in.
Maniac: Love your fix. So much more interesting than it would have been without the "mistake".
This is highly untechnical but I just measure the widest width and length than add and an extra 6 to 8 inches. Remember anything that is left over goes in the scrap heap and is not really wasted.

There is a free craftsy class called "Creative Quilt Backs" with Elizabeth Hartman. She does a VERY mathematical and graphical method for calculating quilt backs. She also shows some neat backs using pieced fabrics, etc. Worth taking the time to watch, just for the assistance in planning your back.

Jan in VA, as always, I so appreciate your graphic pictures. It's just so much easier to understand a concept when it's drawn out.

Puttergeo, Check out some of the backs that Bonnie Hunter of Quiltville purposely puts on her quilts. Pieced, pieced, pieced. One would never be able to detect a "mistake".

Jan in Va - Thank you for the graphics. I save all your helpful posts.
A friend who sewed professionally taught me to work out how much extra I need across the quilt and cut twice that much extra on the length. Then cut that in two across the width, join the short sides then turn sideways and attach to the side. I've done this a couple of times and it does work.

I posted a tutorial a while back when I had the same problem. What I did was to lay the backing exactly diagnonal, which leaves some large triangles where it overlaps the front of the quilt. Cut off those triangles from the backing and move them to the places where the quilt doesn't have backing over it. I'd post a photo, but unfortunately I'm at work!

Thanks JAN for the graphics -
I prefer to make my backs in the "style" of the top left and the three on the bottom because they look like they have been 'planned' and not "ooopsie - I ran out of fabric and just sewed on some more to make the back big enough".

There have been times when I've received donation quilts to quilt, that I've actually taken the backs apart to make them look "planned" instead of "oopsie". Donation quilts should look great too!

MANIACQUILTER - that's an awesome back! That's the kind of back that will gather an 'wow' when people see it. NEVER mention to the recipient the error that got you to the awesome back! Hahahaha! Let them think you 'planned' it that way! You talented girl you!

I do the "mathematical and graphical method for calculating quilt backs"....no sense in tossing around extra fabric or tops if I don't have to. No getting on the floor here.

I will be making two creative backs this week and will post pictures....if I remember! Hahahaha!

Nan