How to Hem Jeans without Measuring

Use an pair that fits as a template!

Jeans stacked with longer pair on bottom

How Hems on Jeans are Different

The yellow stitching and puckered edge give the jeans their classic look. This technique moves the hem edge up the pant leg to preserve that factory look.

Line up inseams

Wash and dry the new jeans the same way that you will handle them in the future. Lay both pairs face down with the longer pair on the bottom. Line up the inseam where the legs come together at the top. The butt seam won’t lay flat because of the curve, so lift the points up together.

Line up and smooth out the legs, starting at the top working towards the ankle. The side seams do not have to be visible on top, so just line up the legs so they lay flat together.

Line up inseams and lift together

Align the Hems

Note the yellow hem stitching on the shorter pair. Roll the longer leg up in a single cuff until its yellow stitching is lined up with the shorter pair. 

Line up the yellow seams

Pin & Press

Insert pins parallel along the existing hem on the long leg following the seam very closely. Ideally use metal or glass-head pins so you can iron over them. Press the pinned area smooth for more professional results.

Ironed leg vs not ironed

Check the Length

Turn the cuff back into the leg, the extra fabric will be a ring-shaped pocket inside the leg. Repeat with the other leg and then CAREFULLY try them on and verify fit. 

Note: Sit down to try them on, because pins and jumping don’t mix!

Turn excess fabric inside leg

Excess fabric now inside

Sew Close

After you verify length, turn the excess fabric back out so that the leg is back to a single cuff again. Note: The pants should be right-side-out when you sew, not inside-out like some other pants hemming projects. 

Place the existing yellow stitching barely under the left side of the presser foot. The new stitching will be about 1/8” from the original yellow seam.

Use a straight-stitch with a matching or slightly darker thread. These jeans are dark-rinse, so I used navy colored thread. If you don’t sew often, practice on a scrap to make sure the stitching looks right before you sew on your jeans.

Original stitching 1/8 inch from new seam

Trouble shooting bad stitching: 
Check if the machine is threaded wrong, the bobbin facing the wrong way, the (thread) tension not set at medium, or the needle is too fine so that the thread doesn’t fit in the groove around the eye.


So... Why is the new seam offset?
We don’t stitch directly over the yellow seam because of the thickness of the fabric. If we stitched directly on top of the yellow thread we would not be able to see the yellow thread when the fabric was turned right side out.

This is because folding fabric isn’t like creasing a flat sheet of paper; the fabric is thicker so it’s more like a U-turn. This difference means that the new seam must be a fraction of an inch away from the old one so that the U-turn butts right up to the yellow seam without covering it.
  
Admire the Illusion

This very close stitching hides the new seam in the "ditch" of the old one. In this picture I'm pulling on the fabric apart to highlight the new stitching from the outside view of the fabric. Without tension the seam creates an optical illusion where the new stitching hides in the shadow of the original seam.

New seam visible with tension

Trim

Cut away excess fabric about ¼” of the new seam. The two side seams are very thick and hard to cut through, to make it easier; make two cuts parallel to the side seams (stopping ¼” away from the new seam). Then you may cut across the tab without risking a mistake from slipping.

Bind

Sew a zigzag stitch casting over the raw edge near to the new seam. Place the cut edge barely touching the right side of the presser foot, so that the needle clears the raw edge of the fabric on the right stroke of the zigzag stitch. Repeat with other leg. Turn the bound edge inside the leg and press the seam open while gently tugging it more flat. 

Zigzag stitch over raw edge

Admire the illusion of a factory hem! 

New shorter length

Bonus

Save the scrap to use for patches later. Buy iron applique backing from the fabric store and make them no-sew if you want.

Enjoy!