How to sew pajama pants: flannel PJ pants for Christmas

To sew pajama pants, cut two fronts and two backs, sew the side seams and inseams, join the legs at the crotch, then fold over an elastic casing at the waist and hem the legs. The free Barrel Pants pattern is built this way, in sizes XS to 3XL, with a 1½ inch elastic waist and optional pockets. It takes about 2 hours. In flannel, wash the fabric first and cut every piece facing the same way. For a quicker gift, the free Sleep Shorts take about an hour.

TL;DR

• Long pants: Barrel Pants, intermediate, about 2 hours. Shorts: Sleep Shorts, beginner, about 1 hour. Both are free and run from XS to 3XL.
• Fabric: 2¾ to 3¼ yards of 45 inch fabric for the pants, 1 to 1¼ yards for the shorts.
• Flannel: wash and dry it before you cut, and lay every piece in one direction.
• Waist: 1½ inch non-roll elastic, cut to the waist measurement minus 2 inches.
• Christmas is Friday, December 25, 2026. Aim to finish by mid-December.

Which pattern should you use?

Both patterns are sized by hip and use the same elastic. Pick by leg length and by how much time you have.

The Sleep Shorts list flannel by name. The Barrel Pants list drapey, medium-weight wovens instead. A soft, light cotton flannel also works for a pajama pair, but that is general guidance, not the pattern's own list. Flannel is a little thicker than linen, so the legs will look fuller.

On iPhone, search “Sewzy” on the App Store for the step-by-step guide and every size.

What size should you make?

Measure around the fullest part of the hips and pick the size that matches. If the pants are a surprise, lay a favorite pair of loose pants flat, measure straight across the hips and double it. Compare that number with the finished hip in the table.

The Sleep Shorts have 8 inches of ease at the hip for a relaxed fit and a 3 inch inseam.

How much flannel do you need?

Cotton flannel is often sold about 42 to 45 inches wide, so check the width on the bolt and use the 45 inch column. Flannel can shrink more than quilting cotton, so a little extra fabric is a safe habit. If you plan to lengthen the legs, buy more to cover the added length. These buying tips are general guidance.

You also need 1½ inch non-roll elastic, matching thread, an 80/12 needle and a safety pin or bodkin to thread the elastic.

How do you prepare flannel?

• Prewash it. Wash and dry the flannel the way the gift will be washed. Most shrinkage happens in the first wash. The Sleep Shorts pattern says to wash and dry the fabric before cutting.
• Check the nap. Flannel is brushed, so it has a soft surface with a direction. Stroke it. One way feels smoother. In some light, the two directions look like slightly different shades.
• Cut one way. Lay every piece with its top pointing the same way. This keeps the color even and keeps reindeer, trucks or words the right way up on both legs.
• Cut on the grain, not the print. Prints on flannel are sometimes a little off grain. Fold it selvage to selvage and follow the fold, not the stripes.
• Finish every seam. Flannel frays. Zigzag or overlock each edge as you go. See how to finish seams without a serger.

These flannel tips are general guidance and apply to any pajama pattern.

How do you sew flannel pajama pants, step by step?

These steps follow the Barrel Pants pattern, with its plain elastic waist option for a classic pajama look.

1. Check the length. The pattern's suggested uses include a cropped hem. For full-length pajamas, compare the pattern's inseam with a pair the person likes. Lengthen at the lengthen/shorten line before you cut.
2. Cut. Print your size, chosen by hip, and tape the tiles. Cut 2 fronts and 2 backs as mirrored pairs, and 4 pocket bags if you want pockets. Transfer the notches and the waist, lengthen/shorten and hem lines. Cut the elastic to the waist measurement minus 2 inches.
3. Pockets (optional). Pin a pocket bag to each front and back side edge between the notches, right sides together. Stitch ¼ inch and press the bags away from the leg. Skip this step for a pocketless pair.
4. Outseams. Put each front on its back, right sides together. Sew the side seams ⅜ inch from waist to hem, around the pocket bags in one go. Press the seams toward the back and the bags toward the front.
5. Inseams. Fold each leg right sides together and sew the inseam ⅜ inch from hem to crotch point. The back inseam is a touch shorter, so ease the front to it. Press open.
6. Crotch seam. Turn one leg right side out and slip it inside the other, right sides together. Match the inseams and notches. Sew the whole curve from the front waist to the back waist at ⅜ inch, then sew it a second time for strength. Clip and press.
7. Waist casing. Finish the top edge. For a plain elastic waist, fold 2¼ inches to the inside instead of the 3¾ inches used for the paperbag ruffle. Stitch close to the finished edge, leaving a 2 inch gap at the center back. Thread the elastic, overlap the ends 1 inch, stitch them and close the gap.
8. Hem. Press the hem under ⅜ inch, then fold on the hem fold line (1¼ inches) and topstitch. Press the whole pair.

How do you get the elastic waistband right?

Cut the elastic to the waist measurement minus 2 inches. For a size M with a 32 inch waist, that is 30 inches. If you can, wrap it around the person's waist before you join the ends. For a surprise gift, use the waist from the size table.

Pin the trailing end of the elastic to the casing so it cannot slip inside while you thread it. After you join the ends, spread the gathers evenly. As general guidance, a short line of stitching through the casing at each side seam stops the elastic from twisting in the wash. Our elastic waistband guide walks through the casing in detail, and the elastic length calculator gives a starting length.

How do you hem pajama pants?

The Barrel Pants hem is pressed under ⅜ inch, then folded 1¼ inches and topstitched. The Sleep Shorts hem is folded ½ inch, then ½ inch again. Flannel is thick, so press each fold with steam before you sew. A slightly longer stitch also helps over the layers. This tip is general guidance. For more ways to hem, read how to hem pants by hand and machine.

Need a quicker gift? Sew the Sleep Shorts

The Sleep Shorts use one pattern piece, cut twice on the fold. The fold is the side seam, so there is no side seam to sew. You sew the inseams, then the crotch seam twice, first at ⅜ inch and then at ¼ inch. Next comes a casing folded ½ inch and then 1¾ inches, and finally a ½ inch double hem. The pattern notes that an old duvet cover makes two pairs. Add the free Boxy Tee for a full pajama set.

How do you turn pajamas into a Christmas gift?

• Plan the weekends. Buy and wash the flannel on November 7–8. Cut and sew the pants on November 14–15. Use the next weekends for a second pair or the shorts.
• Dress the goose too. If the family has a porch goose, the Porch Goose Pajamas Outfit is a Premium pattern. It is a striped dress with a round white collar and a sleep cap with a white pom-pom, for 17, 23 and 27 inch geese. More ideas are in porch goose pajamas and an ugly sweater.

Common mistakes

• Skipping the prewash. The pants shrink after the first wash, not before.
• Cutting two of the same leg. Fronts and backs are mirrored pairs. Cut through two layers, or flip the pattern for the second piece.
• Sewing the crotch once. It takes the most strain. Both patterns sew it twice.

Looking for more to sew? Browse the free sewing patterns. When you are ready to print a size, get Sewzy on the App Store.

FAQ

How much fabric do I need for pajama pants?

For the free Barrel Pants pattern, sizes XS to L need 2¾ yards of 45 inch fabric, XL and 2XL need 3 yards and 3XL needs 3¼ yards. On 58 inch fabric it is 2½ to 2¾ yards. The Sleep Shorts need 1 yard for XS to L and 1¼ yards for XL to 3XL.

Should I prewash flannel before sewing pajama pants?

Yes. Cotton flannel shrinks, so wash and dry it the way the finished pants will be washed before you cut. If you skip this, the pants can come out of their first wash shorter and tighter.

What elastic is best for pajama pants?

Both patterns use 1½ inch wide non-roll elastic, cut to the waist measurement minus 2 inches. For a 32 inch waist, that is 30 inches of elastic.

How long does it take to sew pajama pants?

The Barrel Pants take about 2 hours and are rated intermediate. The Sleep Shorts take about 1 hour and are rated beginner. Plan extra time the day before to wash and dry the flannel.

Does nap direction matter on flannel?

It can. Brushed flannel may look a little lighter or darker depending on which way the nap runs. Cut every piece with the top of the pattern pointing the same way, and directional prints will all face up too.

Related guides: how to sew sleep shorts.