So today I'm going to show you how to hem jeans. There are two ways to do this. First, you could just do a basic hem: measure, cut, fold over and sew; but since most jeans now a days are all fancy and distressed, most people want to keep that look at the hem. Since it's impossible for even a professional seamstress to get that kind of distressing on a new hem, we'll cut off the old one and sew it back on higher up on the jean. Now I just want to say if you're taking up an extremely flared pair more than 3 inches, you might need to actually take in the sides of the jean before attaching the hem since they will probably be different widths.
Ok, so before doing any hemming on jeans, I suggest you wash and dry them at least 2 times. Jeans are made of cotton and cotton shrinks. It may be that if you need them less than an inch shorter that the dryer will do all the work for you. When you hem before washing you always run the risk of the jeans shrinking later and then you're stuck with too short pants.
Well, now that you've got your freshly washed jeans, let's do some measuring. You can either have someone else mark where you want the jeans to hit while wearing shoes (don't ever measure yourself, it never comes out right) or you can measure another pair that fit you perfectly. To do this, take your measuring tape and start at the crotch seam. Measure all the way down the inseam to the hem. As long as this pair doesn't have a horribly droopy crotch, you should be good to go.
So in my demo, I'm going to be shortening my jeans both 2 inches and 1 inch. There are some short cuts you can take when only bringing the hem up 1 inch.
So now we're going to measure up 2" from the bottom of the pant. Don't worry about adding seam allowance, it all evens out at the end. Then measure 1/2" from the edge of the previous stitching (see picture to the left) and cut off the extra fabric. You can save this just in case your jeans shrink later and you need to try and lengthen them. (This is super complicated though, so double check all your measuring.)
Now we're going to cut out the extra seam allowance from the bottom of the side seams. This gets rid of the bulk that you get from having many layers of fabric all sewn together. Just cut right along the side seam without cutting the thread holding it together. Then cut right above the previous hem. See the picture to the right for a visual.
Next we line up the hem section with the rest of the pant leg. Make sure you don't mix up the right and left legs or the seams won't line up properly. Once you have the fabric pinned together (right sides facing inside), we're going to sew right along the fold of the hem. As you can see to the right, I have my middle mark on the presser foot acting as a guide. Try to get as close to the fold as you can without catching any of it in the stitches.
Once you've sewn the two pieces together either serge the edges, or if you don't have a serger, you can zig-zag right along the raw edge. Use a very wide, tight zig-zag so there is no fraying when they're washed.
Now, at this point I'll get into doing it with only taking 1" off. Instead of cutting the fabric, you're going to measure and mark 1/2" from the stitch line (left) and then fold and pin. This way, after it's sewn you'll have a finished edge inside and not have to worry about serging or zig-zag stitches. The rest of the steps are the same.
Press the fold open, making sure you pull the leg of the pant taut so the contrast stitching shows. Flip it over and press from the right side to make sure you get a good crease.
Now we want to choose a thread color that matches the pant color as best as possible. Top stitch right along the seam we just made. I found after a washing, the extra fabric actually folds down and can peek out under the original hem. To avoid this, we'll just stitch it up so it stays out of sight. You can just leave it without the top stitching, or you could even match the color of the decorative stitching and make it look like a double needle has been used.
And with that you're all finished!
Before
After