Could using the 'Golden Ratio' help here? I've tried it sometimes and it seems to work.

I let the quilt talk to me. I piece the inside of the top and then audition borders, either from my stash or at the quilt shop. I find that I tend to like a narrow inner border, generally around 1-2", to frame the top and a wider outer border to finish it off, but that can change. The narrow inner border tends to be darker, but not always. To audition border fabrics, I lay out the candidate fabric then lay a corner of the quilt top on top of the fabric, leaving the border width of the fabric showing so that it looks like you're looking at the actual finished quilt. Then you can move the quilt top in and out, then step back until you get a look that you like. Write down the width of the fabric and use that for your border. You can do the same thing with as many border fabrics as you want.

There are also some general rules of thumb, but they are really a starting point and the final decision should be what looks good to you. Generally, I've heard that the border should be somewhere between 1/2 the block size to the full block size. Here is one discussion of border widths that you might find helpful:

http://stitchintherapy.blogspot.com/2010/01/bordershow-wide-do-i-go.html

This is one that came up from searching on "quilt border width formula". There were several others, too. You might find it helpful to read those. But the most important thing is to follow your heart and trust what looks good to you.

hmm. I often design my own quilts, so am making up borders as I go (or in the design process).

Sometimes I do no border, sometimes a narrow, then wide, then narrow border. When I do add borders, I like for the wide border to be maybe 1/4 to 1/3 the block size, maybe up to 1/2 depending on if I am doing narrow/wide/narrow or just one wide border. If I'm doing narrow and wide, then the narrow one I make around 1/3 or 1/2 the size of the wide border.

I have a computer program that I use (EQ7) so I play with it until it seems in proportion.

Otherwise, I determine border size by figuring out what total size I am aiming for in the quilt (am I trying to get a lap/throw up to twin size? A twin pattern up to full size?), then subtract the main top size from that, divide the remaining width in half and as long as that works (ie, is not giving me a border that is wider than the actual blocks) use that size. Or, if it is larger than I want for one single border, then split that out into a narrow border and a wider border. Repeat that process for needing to add length, and before cutting any fabric, make sure to start with whichever border is narrower .

For example, if you only need 8" added to the length, but need 12" added to the width, that means a 4" border top & bottom, so then be sure to subtract also the 4" on left and right, leaving you with only 4 more inches needed on the width, so then decide...do you want to add a narrow 2" border only on the sides? Add it on all sides, and end up longer than you need? etc.... And of course remember to cut .5" wider than the measurement you want to end up with, to allow for seam allowances.

Always put the narrow one inside, though, so that in the end you have the wider one out for trimming; more forgiving that way if it ends up not quite square and then ends up narrower than intended.

If I'm not making myself clear, let me know, I'll try and explain better.

I have a hard time deciding on the correct border after the quilt top is finished. I can't find information on correct width. Or how many border strips to use. Is there a rule for this, or is it trial and error. Thanks for any help.