Transform Regular Jeans Into Bell Bottoms by Adding Fabric Panels to the Legs

Bell bottoms start with a fitted thigh and knee, then flare out dramatically from mid-calf to the hem. The fastest way to make them is to buy a pair of jeans that fit well in the waist and thigh, then cut open the inner seam of each leg and insert triangular fabric panels that create the flare. This method takes four to six hours for a beginner and requires only basic sewing skills—you do not need to unpick and rebuild the entire leg from scratch.

The alternative is to start from a pattern and sew bell bottoms from flat fabric, but that demands fitting experience and takes twice as long. Most home sewers find it easier to modify jeans they already own or buy secondhand, because the waistband, zipper, and thigh fit are already solved.

Key Takeaways

  • You will need a pair of well-fitting jeans, contrasting or matching fabric for the flare panels, a seam ripper, scissors, pins, and a sewing machine that can handle denim.
  • The inner seam of each leg is cut open and a triangular panel is sewn in to create the flare, starting at mid-calf and widening toward the hem.
  • Measure the width you want at the hem before you cut anything—bell bottoms typically measure 20 to 24 inches around at the opening, compared to 14 to 18 inches for regular jeans.
  • Pressing seams flat with an iron after each sewing step prevents puckering and makes the final hem look professional.
  • The hem should be sewn by hand or with a blind stitch to avoid a visible line of stitching on the outside of the leg.

Measure and Mark Where the Flare Begins

Put on the jeans and have someone mark with chalk or a washable pen where you want the flare to start—usually at mid-calf, about 16 to 18 inches up from the hem. Stand in front of a mirror and mark both legs at the same height. Take off the jeans and lay them flat on a table.

Measure around the leg at that mark with a soft measuring tape. Write down the measurement. Then measure around the hem opening. Subtract the hem measurement from the flare-start measurement to find how much width you need to add. If your calf is 14 inches around and you want the hem to be 22 inches around, you need to add 8 inches total—4 inches per leg, or 2 inches on each side of each leg.

Cut Open the Inner Seam and Prepare the Panels

Use a seam ripper to carefully cut the inner seam of each leg, starting at the flare mark and going all the way down to the hem. Work slowly so you do not cut into the fabric itself, only the thread. Pull the thread away as you go. Once both legs are open, press the seam allowances flat with an iron.

Cut two triangular panels from your flare fabric. Each panel should be as tall as the distance from your flare mark to the hem (usually 16 to 20 inches). The top of the triangle should be narrow—about 1 inch wide—and the bottom should be as wide as half the total width you need to add, plus 1 inch for seam allowances on each side. If you need to add 4 inches per leg, each triangle's base should be about 6 inches wide.

Pin the triangular panel to one side of the opened seam, with the narrow end at the top and the wide end at the bottom. The raw edges should line up. Sew along both long edges of the triangle using a straight stitch and a 1/2-inch seam allowance. Repeat for the other leg.

Press Seams and Try On for Fit

Press both seams flat with an iron, pressing the seam allowances toward the jeans fabric. This step prevents the seams from puckering when you wear the pants and makes the flare hang smoothly. Try on the jeans to check the width at the hem and the overall shape. If the flare is too narrow, you can add more fabric by opening the seams again and inserting wider panels. If it is too wide, you can take in the seams by 1/4 inch on each side.

Walk around in them for a few minutes. The flare should feel balanced and not pull at the thigh or waist. If the fit is right, move on to hemming.

Hem the Legs by Hand or Machine

Decide on your finished hem length by putting on the jeans with the shoes you plan to wear them with. The hem should just touch the top of your shoe or break slightly on the instep. Mark the length with chalk or a washable pen all the way around both legs, then try them on again to confirm.

Cut off the excess fabric 1 inch below your mark. Fold the raw edge up 1/2 inch and press it with an iron. Fold it up again 1/2 inch and press. Pin the fold in place all the way around the leg.

Sew the hem using a blind stitch by hand or a blind hem stitch on your machine. A blind stitch hides the thread inside the fold so the stitching does not show on the outside of the leg. If you use a machine blind stitch, test it on scrap fabric first—the needle should catch only one or two threads of the jeans fabric as it swings out, so the stitch is invisible from the front. Hand sewing takes longer but gives you more control and is less likely to pucker on heavy denim.

Common Mistakes to Avoid

Do not cut the outer seam of the jeans—only the inner seam. The outer seam holds the leg shape and is much harder to repair if you damage it. Mark your flare start point carefully before you cut anything; if you start the flare too high, the jeans will look awkward and baggy through the thigh.

Do not skip the pressing step. Pressing seams flat after you sew them is what separates homemade bell bottoms from store-bought ones. Unpressed seams will pucker and twist as you wear and wash the jeans. If your iron is not hot enough, the seams will not stay flat; use the cotton or linen setting and press for at least 10 seconds on each seam.

Do not use a regular straight stitch for the hem on denim. A straight stitch will break when you bend your leg because denim stretches slightly and a rigid line of stitching cannot give. A blind stitch or a stretch stitch will move with the fabric. If your machine does not have a blind stitch, use a narrow zigzag stitch instead.

Choosing Fabric for the Flare Panels

The easiest choice is to use the same weight denim as your jeans, in the same color or a contrasting color. Matching denim blends in completely and looks like the jeans were made that way. Contrasting denim—a lighter or darker shade—creates a visible panel that looks intentional and vintage.

You can also use cotton twill, corduroy, or cotton canvas, which are all sturdy enough to hold the flare shape without sagging. Avoid lightweight fabrics like cotton print or chambray; they will not support the flare and will look droopy. If you want a patterned look, choose a print that is bold enough to read from a distance—small prints disappear on a flared leg.

Buy at least 1 yard of fabric to have enough for both panels plus mistakes. Prewash the fabric in the same water temperature you use for your jeans so it shrinks at the same rate and does not pucker after the first wash.

Frequently Asked Questions

Can I make bell bottoms from pants other than jeans?

Yes. Corduroy, twill, and canvas work well because they are sturdy enough to hold a flare. Avoid stretchy fabrics like knits or spandex blends—the flare will twist and sag. Cotton dress pants are too lightweight and will not look right. The original pants should fit well in the waist and thigh; if they are already too loose, adding a flare will make them look sloppy.

How much fabric do I need for the flare panels?

One yard is enough for most bell bottoms. You need two triangular panels, each roughly 16 to 20 inches tall and 4 to 6 inches wide at the base. One yard of 45-inch-wide fabric gives you plenty of room to cut both panels and make mistakes. If you are using a patterned fabric and want the pattern to match on both legs, buy 1.5 yards to account for pattern placement.

What if I do not have a seam ripper?

A small pair of scissors or a craft knife works, but a seam ripper is safer because the curved blade is designed to slide under thread without cutting fabric. You can buy one for two to five dollars at any fabric store or online. If you use scissors, work very slowly and pull the thread up slightly as you cut so the blade does not slip into the fabric.

Do I have to hand-sew the hem?

No, but a machine blind stitch or hand blind stitch looks better on denim than a regular straight stitch because it does not show on the outside. If your machine does not have a blind stitch, a narrow zigzag stitch is the next best option. A regular straight stitch will work but will be visible and may break when you bend your leg.

Can I add bell bottoms to pants that are too tight in the thigh?

Not easily. Adding flare panels only widens the leg below the flare mark; it does not change the thigh fit. If the thigh is too tight, you would need to open the side seams and add panels there too, which is a much more complex project. Start with jeans that fit well in the waist and thigh, and use the flare panels only to widen the calf and hem.