How long to cut each border strip? formulae?
 

I cannot seem to wrap my head around how long each border strip needs to be cut (sides, top, bottom) with consideration of seam allowances --- especially when designing with multiple borders.

To cut the top/bottom border, I take the width of the quilt top x the desired width of the finished border plus .5 for seam allowance. The sides totally confuse me because of the seam allowances.

As you can see, I am confused here.

Is there a formula for doing this? ...

Your formula doesn't make sense to me. You said width of quilt top x desired width of finished border plus half an inch for seam allowance. So if your top was 50" and the border was 6", you would ADD, not multiply.

Let's say you're going to sew borders onto the sides (east and west) of your top.

border + quilt + border = 6 + 50 + 6 = 62".

Now, all the plus signs (+) in the above equation are where there are seam allowances. If you're sewing quarter inch seams, that means the seam is taking in half an inch (.25 for the border fabric and .25 for the quilt top, which equals half an inch). There are 2 pluses in the equation, half an inch for each one, for a total of 1 inch. So after sewing on both borders, the finished width of the quilt should be 61".

Now you add the borders to the top and bottom (north and south) sides of your top.

6 + 61 + 6 = 73"

Your top & bottom borders should be cut at 73" long.

Does that help?

Peggi - recheck your calculations.


It's very simple. Measure the length of the quilt (in several places and take the average). This is the length to cut the side borders. Sew them on.

Now measure the width of the quilt with those borders included. This is the length to cut the top and bottom border.

If you want to cut all the borders before you start sewing, you still measure to get the first measurement. That is the length to cut the side borders. Then add to this 2 times the finished width of the borders and that is the length to cut the top and bottom borders.

I do basically as dunster stated.

First I measure the length from the center of the quilt top to get my measurement. I sew the long sides first. Then I measure the width from the center of the quilt to get my measurement then I sew my widths. I do add a tad more for wiggle room. Better to have too much than not enough. Just trim the difference. If I want one finished 5 inch border I'll add 1/4 inch to my border strip and cut at 5 1/4.

Also, I find my centers of quilt and borders and attach with pins from the center working to the left then from the center working to the right. I was told doing it this way will keep you borders/quilt from being wavy.

dunster,
There is nothing wrong with peggi's calculations.....

You wouldn't subtract the inch from the top and bottom borders
because you would be sewing the sides of the borders.....the seam allowance would
come out of the width of the fabric......if that is what you think is incorrect.

1st off when measuring how long to cut for your borders, measure from the middle of your quilt as the edges might have gotten stretched and you'll end up with wavy borders if measured from the edges. 2nd most times the sides go on 1st then the top and bottom and again you'll measure from the center of the quilt or at least measure from the center and again on the edges and then average it out. I measure from the center only and normally have issues with wavy borders. I cut each border and attach when I am adding multiple borders unless I'm doing them mitered style, then I might stitch all the borders for each side/top/bottom together and then attach but you have to allow for extra length so you can miter the corners. I rarely miter my borders unless I'm using a striped fabric and want the stripes to meet up correctly. The adding .5 for seams, well if you think about it the outer .25 seam will be encased with the binding so you're really not losing that measurement at all. Just my thought on this subject.

also important is to match the middle of the border strip and the middle of that side of the quilt, pin. then pin the ends of border and quilt. i pin a bit in between too. all should lay nice and flat. then sew. Have fun!!

This method is the least complicated. But be sure to measure your quilt in several places in the Middle, not at the edges. Average out these measurements and cut both borders the same length as that average. Sew them on.
Then do the same with the other sides: measure several places in the middle, including the first borders, average those measurements, and cut both borders the same.

I measure using my border fabric. I first fold top exactly in half, lay border fabric on the fold and lightly smooth to the end of top. Then I mark where it should be cut. Lay other border strip under first and lightly smooth to the mark and pin those two ends together, cut on mark of first strip. Sew onto top. For ends I do the same as for sides. Fold top exactly in half and continue to do as I did for the sides/ length. People do things differently to get the same results.

There should be youtube videos to show how the "experts" do it. Try a few different ways to see what results you like best. My way works best for me. I have been making quilts since mid 1960s.

What's wrong with them, where did I go wrong? The math is correct, so....?

The OP was asking for a formula and expressed confusion about the seam allowances. I thought I gave clear explanation of both.