Is there a way to make a sewing pattern larger?

It depends on how much you need to add. Adding 1/4" to the side seams will give you an extra 1" all over.

The pivot and slide method is for more extreme alterations - http://www.threadsmagazine.com/item/4498/the-merit...

Make a muslin first, noting any adjustments that need to be made to the original pattern before cutting out the fashion fabric.

Executive summary: smallish changes, usually not an issue. Going up more than a size is usually going to cause at least some problems, sometimes major ones, and will definitely require a fitting muslin. Sometimes it's easiest if you just find a pattern in the correct size that has a similar silhouette and modify it.

What's the pattern and what do you need to do to it?

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It's called grading if you're going up all over in size. Overgrading is usually a recipe for disaster -- the grade rules usually fall apart more than about 2 sizes away from the base size. For instance, if a company wants to sell sizes A through J dresses, they will probably create the base design in size C,

and then grade down to an A and up to an E : a<-b<-C->d->e Then they'll make a new base design in size H and grade that one down to a size F and up to size J : f<-g<-H->i->j

Here's the basic idea behind grading: http://www.threadsmagazine.com/item/4368/making-se... http://www.threadsmagazine.com/item/4424/quick-ref...

If you're just adding in a couple of areas, perhaps to the hips, then you just want to alter the pattern in that area and leave the rest of it alone. With simple patterns, adding to the side seams in that area will do it, but you can get yourself into trouble there, too. For instance, if you decided to add 1" to the side seams and extended that from the hips up to the armscye, all of a sudden, your sleeve won't fit into that armscye -- the armscye is now 2" bigger around. It gets worse when you've got a fitting seam that requires you to sew a convex to a concave curve, like the bust area of a princess seam. The concave seam line will get shorter if you just decide to sew that seam with a 1/4" seam allowance instead of a 5/8", and the convex seamline will get longer. And then things really don't fit.

The alteration method I find most people intuitively grasp is to draw in the stitching line on the pattern. Cut along the stitching line and move the whole seam allowance out, patching in new paper. You now have more fabric in that area to cover the body, but you haven't changed the seamline lengths -- so the sleeve will still fit, the princess seams will still sew, etc.

http://www.threadsmagazine.com/item/5053/the-seam-...

Finally, there's one other hitch to changing patterns drastically. Say you want to use a child's design for an adult, or vice-versa. Kids and adults have very different body shapes and proportions, and you really just need to choose a similar design in the right body silhouette and redesign it to resemble the design you wanted. See: http://www.fashion-incubator.com/archive/grading_i...