Jeans are a wardrobe staple and, at the same time, one of the most commonly altered garments - learning how to hem jeans is essential. Finding the perfect length can be challenging for some and understanding how to hem a pair will prove helpful to you sooner or later.

Once you learn the basics, you will be able to quickly hem jeans and save time and money from going to a tailor shop.

How to Hem Jeans: Step by Step Tutorial

In this article, we'll explore two methods of jean hemming: preserving the iconic original hem and creating a new one with step-by-step instructions, guidelines for sewing with denim, and many other tips on how to sew jean hems.

The anatomy of jeans 

Before we dive into the hemming, let’s define three jean components important to the process of hemming:

The inseam is the seam running down the inside of each jean leg. This seam usually experiences more wear and tear, and that is why it is finished as a flat-felled seam to add strength and jean longevity.

The inseam is used to describe the length of pants. For example, for jeans with a "38x36" size, 38 is the waist size and 36 is the inseam length. 

The outseam is the seam running down on the outside of each leg. This seam runs from the waistband down to the bottom of the hem.

Hem is the finished edge at the bottom of the jean leg. Most of the hems feature distinct topstitching and distressed looks.

Types of Hems for Jeans

1. Original Hem - Keeps the original hem intact and reattaches it after shortening the jeans.

2. Traditional Hem Involves cutting excess length and creating a new hem. The new hem will no longer have the “distressed” look of the original jeans.Both methods have their pros and cons, and you will have to choose based on the jean type, sewing skills, and the look you want to achieve. The original hem method keeps the original stitching and hem finish, but could be bulky depending on the denim weight. On the other hand, the traditional hem creates a new, clean finish that is not bulky, but it removes the original stitching and finish.
Besides the traditional ways of hemming a pair of jeans, you could also do:
A raw hem: Cut to length and leave the edge raw and secure with a straight stitch just above the edge to control fraying.
A frayed Hem: Similar to raw but manually pull some threads for a distressed look.

Guidelines for sewing with denim fabric

Choose the right sewing needle - Depending on the denim thickness, choose an appropriate denim/jean needle. Jean needles have an extra-sharp tip for penetrating the thick fabric and have a bigger eye to accommodate thicker threads. Use a 90/14 needle for light to medium-weight denim and a 100/16 or 110/18 for heavyweight denim. In the case you do not have any denim needles, then universal needles work just fine and achieve neat stitches.

Choose a strong thread - A heavy-duty thread ensures that the hem is durable but also adds detail to topstitching since these types of threads are thicker. But keep in mind to always use a regular thread on your bobbin.

Press as you go - When pressing denim, use the high temperature cotton setting and apply steam when necessary. Since denim is quite thick, more pressing than usual might be needed.

Lengthen your stitch length - A common stitch length of 3-4 mm is recommended for sewing denim.

How much hem allowance is enough? 

The hem allowance width is typically determined based on the garment and fabric type. For thicker fabrics such as denim, a larger seam allowance is recommended to provide structure and stability to the hemline. Always leave a minimum of ¾ in (2 cm) hem allowance.

Jean traditional hem – step by step tutorial

1. Try on the jeans to determine the desired finished hem length. Mark the position for the new hem with pins or a water-soluble pen. 
2. Lay the jeans on a flat surface and from the new marked hem measure down 1inch (2.5 cm) and mark. Cut along this line (seam allowance line). Repeat for the other leg.
3. Fold the raw edge by ½ inch (13 mm) and press with an iron. Fold again by ½ inch to enclose the raw edge. Press the double-folded hem and secure with pins in place.
4. Thread the top of the machine with denim thread and use all-purpose thread in the bobbin. 
5. With the hem on the right side, begin on the inseam with a straight stitch and sew around the hem close to the inner fold edge.  Repeat for the other leg.

Even though the original hem is lost, if you wash and wear your jeans regularly, then the wavy lines and fading will happen, but it may take time. There are ways to distress the hem, such as using a razor or roughing up the hem with sandpaper.

Jean original hem – Step by Step Tutorial

1. Try on the jeans to determine the desired finished hem length. Mark the position for the new hem with pins or a water-soluble pen. 

2. Next, lay the marked leg flat, carefully aligning the back and front hems and the side seams. Mark around the entire leg at that same height. For example, the distance is 2.4 inches (6 cm). Mark a line with the removable fabric marker.
3. Measure the depth of the original hem from the very bottom edge to the topstitching line. In this case, it is about (13 mm). Draw another 1/2 inch (13mm) line above the first line.  
4.  Make sure that these lines are the same on both pant legs; otherwise, you will end up with uneven hems.
5. Fold up the jeans so that the edge of the original topstitch line is lined up with the top line drawn on the jeans. Secure in place with pins.
6. Use regular sewing thread for both upper and bobbin thread.  
7. Slide the end of the pant leg under the needle and stitch around the hem, trying to sew as close as possible to the original hem and backstitch at the end. Using a zipper foot may help to keep an even seam.
8. Press the created fold of fabric up away from the hem. If this fold is quite wide, trim the excess, leaving 5/8 inch (1.5 cm), and finish the raw edge with a serger or a zigzag stitch.
9. Give the hem a final press and repeat the same steps for the other leg.

This method keeps the original hem intact, and the character of the jeans is not lost, but on the other hand, depending on the denim weight, it can add bulk and create a stiff line around the new hemline. In addition, cuffing jeans is not an option anymore since the inside seam will be visible.

Tips for hemming jeans

• Using the tool of your choice (ruler or sewing gauge), always be sure to mark the hem allowance correctly.
• As with any other sewing technique, pressing is a must, and in order to get a neat finish, press your seams and hems after every step.
• Puckering may happen while sewing hems, so it’s advised to loosen thread tension to achieve a balanced stitch, and in some cases, a needle change may help too.
•  Use a mallet to hammer bulky denim seams and hems before stitching.
• Aim for wider hem allowances to minimize bulk. A 1 inch double folded hem is a good start to finish the jeans.
• Before cutting your final jean hem, always try the jeans with a pair of shoes that you usually wear.

Final thoughts on hemming jeans

Hemming, besides giving you well-fitted jeans, also gives you the satisfaction of updating and extending the life of your wardrobe.

The methods above walk you step-by-step through two ways of finishing a jean hem to create a custom length but at the same time give you an intro into the world of denim alterations. So, we suggest you grab your sewing machine and a pair of jeans and try on your first jean hem!