I'm short. It stinks, because I am about 1/4 inch too tall for petite size pants, but the regular length is way too long. I guess I am a long legged short person- ha,ha. So, buying pants is pretty much torture. Anyway, you know how jeans have a top-stitched hem and to match the tread would be impossible? If you hem without the top-stitching it looks like nerd jeans so don't do it. Well, here is how you hem them while keeping the original hem.
Cut off the hem 1/2 inch above the original hem. This is your seam allowance so you can do 1/4 inch, but with the weight of the denim I think it works better to leave a 1/2 inch seam allowance so it will lay flat. It wasn't me, but whoever sewed the hem did it wonky. It drove me a little crazy.

Now, you need to know how long you want your jeans. I used my favorite pair that fit as a guide. Measure the inseam, which is from the crotch down the leg. I wanted my measurement to be 28.5 inches. I need to allow for 1 inch seam allowance- 1/2 on the hemmed piece and 1/2 on the bottom of the pants leg when sewed will take up 1 inch of fabric.

I measured the hemmed piece I cut off and it was 1 1/4 inches. I need 29.5 inches of fabric so I subtracted 1.25 from 29.5 and got 28.25 inches. That is the length the pant leg should be cut to without the hemmed edge piece added. Make sense? Once I sew the 1.25 inch piece using a half inch seam allowance the length will be 28.5. Below is the extra fabric I cut off the bottom of the leg piece.

Pin the hemmed edge to the bottom. (Hint: if you measure from side seam to side seam the front panel of the pant leg is not as wide as the back panel. When you put the hemmed edge on make sure you have the correct one and they match from seam to seam or you will end up with one side that is puckering and one too short across.)

I put on my zipper attachment since the denim is so bulky along the hem. I then sewed a seam right at the bottom of the hem. You can't see it in this photo because it just blends in, but it is really there, right at the bottom. See where the bottom edge is hemmed with the yellow thread... I sewed on right below the yellow thread at the same spot where the fabric is turned for the hem.

Turn right side out and iron the hem down flat.

This is how it looks on the inside. I think I will take some wonder under or double sided iron on fusable tape and bond the seam allowance down so it doesn't end up flopping around. I will see how it washes and wears first.

There you go all you short people. It was very easy- about 15 minutes from start to finish.