1/4 inch seams
 

I am not sure why that measurement came to be for quilts but I prefer 1/2 inch seams. Does anyone know how to change patterns to 1/2 in seams? If I make my own templates I have changed them but not a pattern made by someone else.
Lynda

You could either add an additional 1/4" on all sides of your piece dimensions, or just use the 1/2" seam and have a smaller quilt.
The third alternative is to add additional finished blocks to the pattern until it is the size you want. That would be my choice.

I know it doesn't seem possible, but back in the day when I started quilted (before rulers) not that much was said about seam allowances. You typically had a cardboard template that was the correct size and you drew around it and sewed on the drawn line, with some sort of seam allowance you didn't worry too much about. Pretty much all we had were black and white block diagrams to work with with no cutting our layout information.

Coming with no family background or training and from the 7/8ths in garments, I used 1/2" seams for my first years in quilting with no problems at. Graph paper is a wonderful thing! In my first ever project I realized that I could buy a "desk blotter pad" (remember those??) with a 1/4" grid, it was something like a 22x14" pad and perfect for fabric folded in half. Sounds basic but always make sure you are 4 squares to the inch! Some grids have different sizes, like architectural is 5 to the inch. I found that out the hard way with half my precisely cut tulip petals had been drawn on the 5 grid...

They have some quilting specific but so many grids here, I still use this site a lot when I'm drawing out a new block:
https://www.incompetech.com/graphpaper/

Some reasons for using a 1/4 inch seam allowance instead of a 1/2 inch seam allowance:

For most closely woven cottony fabrics that the seams will not be exposed, there simply is no need for that extra fabric. The fabric will not pull apart. Notice that I said closely woven. Also slippery fabrics like satins need to have extra seam allowance or the raw edges need to be encased (bound or use a French seam) or overcast so the edges do not fray.

It takes a lot less fabric .

It just gets bulky and harder to handle - especialy when using small pieces in a block. Even using smaller seam allowances, some quilt blocks end up with a big "clump" at some of the intersections.

However - I do have a quilting book that uses wider seam allowances - don't remember if they are 1/2 or 5/8 .

As others have said, you can take the "finished" size of a piece and add 1/2 inch all the way around.
The "finished" size is what shows "on the top" when the item is completed.

I have seen some hand-pieced blocks that the seam allowance is a scant 1/8 inch. I think that is skimpy.

The smaller seam allowances probably came about when people had only scraps to work with and they wanted to get as much "mileage" out of the pieces as possible.

Good points, Bear! I came back to say that you will really notice how different Trigonometry is to normal Geometry when you start turning back those triangle seams.

You can have as much fabric on the back of a small triangle as the front and with the half-inch seam you will notice it and maybe even have to trim them down sometimes.

When I started, 1/4" seemed so amazingly tiny, after years of looking at it even with my declining vision issues, I've decided it's actually pretty darn big compared to the size of thread. By now, some 20 years of rotary cutting the translations of design size+ 1/2" of seam allowance has been driven into me and I just know that the math is to add 7/8ths to the finished size of a right triangle instead of the normal 1/2". I sort of have a mental chart of finished to full sizes in my head.

But I do get confused all the time and I will write out cutting instructions for me, currently there is a computer monitor set up on the other side of my cutting mat and I bought a sticky pad just exactly to use for my cutting notes and I stick it square in the middle of the screen. Sometimes not until after I've already botched stuff up! But I do try to go through my math and make sure what I'm doing is correct. Sometimes I use junk mail and cut it and play with it first, just to make sure.

I think it’s interesting to see how the “standard” seam allowance evolved during the “quick quilt making” revolution in the late 1970’s to now. When Barbara Johanna’s published her books Quick Quilting and The Quick Quiltmaking Handbook in 1976 and 1979 respectively, she suggested a 1/2” seam allowance. By the time Barbara published Crystal Piecing in 1993, the 1/4” seam was the norm (although her technique of mark-sew-cut was the same as in her earlier books, and the cutting was often completed with scissors).

When Mary Ellen Hopkins began teaching quilt shops her techniques in 1982 to allow the quiltmaker to say “It’s Okay for you to Sit on My Quilt”, she used a seam allowance of whatever you got when you lined up your fabric next to your presser foot and then had you use that measurement for the entire quilt. She noted in the revised version of her book from 1987, that often the presser foot measurement was 1/4”.

I have found most quilt patterns have cut sizes that only work if you use a 1/4" seam. Way to much mind work to adjust the pattern. Applique can be any oversize without a problem. Rag quilts use a 1" seam allowance.

I have recently taken to using a 3/8" seam allowance and am very much happier with it!

I started way before rotary cutters, self healing mats and 1/4" seams. Seems some of my intersections line up easier. I use a smaller stitch length harder to rip out but I think seams hold better.

I am happier and use to using rotary cutter and hated to cut with scissors. Very boring cutting out all those squares.

I was used to a much larger seam - 5/8" for sewing clothing, and going down to a 1/4" seam was very difficult for me. But the more I sewed that 1/4" seam, the better and easier it was. I can't even imagine trying to sew a 1/2 inch seam on a 1 or 2 inch HST. Fighting all that fabric would be hard. And, another point, all that extra bulk and weight from the wider seam is going to make all of your quilts heavier. That's okay if you are only doing lap or small throws, but the weight on a king size bed quilt would be too much for me. I'd be popping the piecing and quilting seams every time I tried to move the quilt. Washing the king would be a nightmare. Another point...You are going to have to reinvent the wheel on EVERY pattern you make because ALL patterns these days are written for the 1/4" seam unless you are doing miniatures which sometimes uses a 1/8" seam. Is there a particular reason you want to do the 1/2" seam?