How to Sew Men’s Boxer Shorts: 10 Steps, 1 Yard of Cotton

Most boxer shorts tutorials hand you a pattern and a list of steps and skip the part that decides whether the finished pair gets worn, which is the arithmetic: how much ease goes into the hip, how far the crotch curve reaches, and how much shorter the elastic sits than the waist it has to hold. A pair that rides up or rolls at the waist almost never failed because the stitching was wrong. It failed because two numbers were guessed.

This guide works through the ten steps in the order that prevents unpicking, with a worked example for a 34 inch waist and a 40 inch hip, then the size, seam and elastic charts, the three fly methods compared, and the fixes for the four ways a handmade pair usually goes wrong. It assumes a standard home sewing machine, a woven cotton, and no overlocker.

What Decides Whether a Pair Fits

The arithmetic comes first. Ease is the difference between a body measurement and the garment, and men’s underwear needs very little of it: 2 inches at the hip is enough for woven cotton boxers, because the fabric does not stretch and the legs are open. Add 6 inches and the seat sags. Add none and the shorts split at the crotch the first time the wearer sits down.

The crotch curve is the second number, and it is the one beginners flatten. A curved seam gives the fabric room to wrap under the body; a straight line has to be forced, so it pulls at the front and leaves a fold at the back. Draft it as an arc, not a corner, and the same pair stops fighting the wearer.

The third number is elastic tension, and the fourth is hem allowance. Both are cheap to change and expensive to ignore. The four failures below are what bring people back to a boxer shorts tutorial for a second attempt, and each one traces to a number set weeks earlier, on paper.

Ease is the one to settle first, because it changes every other piece: the front width, the back width and the hem width are all drafted from the hip. Elastic is the cheapest to correct late, and the hem is the only one that can be fixed on a finished pair. In Mithu’s testing, three of those four failures were fixed by cutting the elastic shorter, and the fourth by re-drafting the crotch curve on paper rather than adjusting the sewn garment. Paper is free and ripping is not.

What You Need Before You Cut

A single pair takes very little: one yard of fabric, one length of elastic, one spool of thread. The temptation is to buy a rotary cutter, a walking foot and a serger before the first pair, and none of them is required. A sharp pair of fabric scissors, a ruler, a pencil and a machine that makes a straight stitch cover the entire project.

Buy polyester all-purpose thread rather than cotton for the seams, because it takes the abrasion of a waistband and a crotch seam far better than cotton, and buy more elastic than you think you need so the length can be measured rather than guessed.

Which Fabric Is Best for Sewing Boxer Shorts

Cotton poplin or lightweight quilting cotton is the safest choice for a first pair. Both are stable under the presser foot, hold a pressed crease, and do not stretch out of shape when the elastic pulls the waist in. Cotton lawn and voile are lighter and better for summer, but they fray quickly, so every seam needs finishing.

Flannel is the traditional winter choice and the easiest to sew of the lot, because the brushed surface grips itself and seams stay put while they are pinned. What it does not do is press crisp, so the fly topstitching sits softer than on poplin.

Stretch jersey is the one fabric to leave alone on this pattern. A pattern drafted for woven fabric has no negative ease, so jersey boxers made from it come out baggy at the hip and long in the leg, and the seams need a stretch stitch that a basic machine handles poorly. If knit underwear is the goal, use a pattern drafted for knits and follow the guide to sewing machine needle types to pick a ballpoint needle for it.

Work out the fabric quantity before choosing a print, because a directional print or a one-way plaid cannot be laid out in both directions. A 40 inch hip fits on 1 yard of 45 inch wide goods with the pieces nested; a 46 inch hip needs 1 1/4 yards, or a 60 inch wide cotton, and the chart further down lists both.

Step 1: Take Four Measurements

Four measurements are enough for this pattern, and each has a specific place to sit. The waist goes around the natural waistline, level with the navel. The hip goes around the fullest part of the seat, which for most men is 7 to 9 inches below the waist. The thigh goes around the widest part of the upper leg, standing with weight on both feet. The length is a preference, measured from the waist down the outside of the leg to wherever the hem should sit.

Take them over underwear, keep the tape level, and write them down rather than remembering them. Consistency matters more than precision here: an eighth of an inch of wobble on both legs is invisible, and a half inch corrected on one side only is what makes a pair sit crooked.

The worked example in the rest of this guide uses those four numbers: 34, 40, 22 and 14 1/2. If your hip is larger, only two things change, the width of each pattern piece and the amount of fabric, and every other step stays identical.

Step 2: Draft the Front Pattern

Start on paper rather than straight onto fabric, and draft half the front piece with a centre front line down the left edge. Everything is measured off the hip, so the numbers scale with the wearer.

1. Draw a vertical line for the centre front, then a horizontal line at the top for the waist.
2. Measure down 1 1/4 inches and draw a second line: that is the top of the waist casing.
3. Measure down the finished length plus 1 inch for the hem, and square a horizontal line across for the hem edge.
4. At the waist, square out half the hip measurement plus 2 inches, which is 22 inches for a 40 inch hip.
5. At the hip line, square out a quarter of the hip plus 1/2 inch: 10 1/2 inches.
6. At the hem, square out half the thigh plus 1/2 inch: 11 1/2 inches.
7. On the centre front at the crotch level, mark the crotch extension 2 inches beyond the line, then draw the front crotch curve from that point to the hip line in one smooth arc.
8. Add a fly extension 1 3/4 inches wide down the centre front, from the waist to 7 inches below it.
9. Add 1/2 inch seam allowance on every edge, except the centre front below the fly, which stays on the fold or gets its own allowance if the front is cut as two pieces.

The two lines that matter most are the crotch curve and the top of the casing. Draw the curve with a ruler held loosely rather than a French curve, because the aim is a smooth arc from the extension point up to the hip line, and a French curve tends to make it too deep at the front.

Step 3: Draft the Back Pattern

The back piece is drafted from the front so that the two side seams end up exactly the same length, which is the single most common drafting error in this project. Copy the front piece, then change four things and nothing else.

1. Raise the waist edge by 1 1/2 inches across the whole piece, which gives the seat the extra depth it needs when the wearer sits.
2. Add 1 inch to the side seam, so the back is wider than the front and the side seam falls slightly forward of the true side.
3. Replace the 2 inch front extension with a 3 1/2 inch back extension, so both halves have room to wrap under the body.
4. Redraw the crotch curve deeper and longer, from the back extension point round to the hip line, so the seam clears the seat.

Then check one thing before cutting: measure the side seam on the front piece and the side seam on the back piece with a tape standing on edge. They should be within 1/8 inch of each other. If they are not, the error is almost always in the raised waist edge, because the back is 1 1/2 inches higher and the side seam has to absorb that difference.

Label both pieces with the size, the grainline and a notch at the side seam, then check them against a pair of shorts that already fits. Five minutes of comparison saves a pair of shorts made from fabric you cannot get back.

Step 4: Cut Two Fronts and Two Backs

Most beginner instructions say to cut the front on the fold, which works only if the fly is faked. For a real fly, cut two separate front pieces, mirroring the second one, because the left and right sides of a fly overlap and a folded piece has nothing to overlap. Cut two backs the same way, or cut the back on the fold if you prefer a centre back seam free finish, which is fine for boxers.

Lay the fabric flat rather than folded wherever the yardage allows, so that no piece ends up off grain. The grainline on each pattern piece should run parallel to the selvedge, which is what stops the legs twisting after the first wash. If the yardage is tight, fold the fabric and nest the pieces, but keep the grainline square to the selvedge on all four pieces.

Mark the notches at the side seam and the centre front with a snip no deeper than 1/4 inch, and mark the wrong side of the fabric with a chalk line at each crotch point. When the pieces come off the table and go to the machine, the chalk and the notches are the only things that keep them matched.

Step 5: Sew the Fly

Three methods circulate, and they are not interchangeable. A faux fly has no opening at all: a curved line of topstitching and a bartack suggest a fly, and the waistband holds the front closed. A real fly, sometimes called a placket, has two overlapping extensions with a buttonhole, and takes about 25 minutes longer. No fly at all is the fastest option and is what many pyjama patterns use.

For a real fly, the sequence is what keeps it flat:

1. Sew the centre front seam from the crotch point up to the bottom of the fly, with a 1/2 inch allowance, and press the seam open.
2. Press the right front extension to the wrong side by 1/2 inch, then place it over the left extension so that the two overlap by the full 1 3/4 inches.
3. Pin through all the layers along the centre front line, keeping the overlap flat and the seam itself hidden underneath.
4. Topstitch from the waist down the front edge of the overlap, then curve the stitching across to the centre front at the bottom of the fly.
5. Backstitch two or three stitches at the base of the curve, or add a bartack 1/4 inch long, because that point takes all the strain of sitting.

Press the fly after every stitching line rather than at the end. A fly pressed once, at the end, will show a ridge through the topstitching, and the ridge is permanent once it has been washed.

Step 6: Close the Crotch Seam

The crotch is not one seam but two. Sew the front crotch curve on each leg separately, matching the two front pieces, then sew the back crotch curve on each leg, matching the two back pieces. Only then does the whole crotch seam close, so the curve is worked in short, controllable runs rather than one long seam that shifts under the presser foot.

Clip the curves, not the seam. The crotch curve is concave on the inside, so it needs small snips into the allowance every inch to let it open flat. Snip to within 1/8 inch of the stitching line and no further, and do it after pressing rather than before, because the pressed seam shows where the fabric wants to release.

Press the crotch seam allowance toward the back on both halves, and then, before closing the seam completely, check the seat depth by pinning the two halves together and holding them against the wearer or a pair of shorts that fit. This is the last moment at which the crotch can be changed without unpicking.

Step 7: Sew the Inside Leg and Side Seams

Take the two fronts and the two backs and join them in a specific order: inside leg first, then side seams. Sewn inside leg first, the shorts form a tube that lets the side seam be fitted properly; sewn the other way round, the inside leg becomes a blind seam that is very hard to reach.

The inside leg seam runs from the front hem, up the inside of the leg, round the crotch and back down to the back hem, in one continuous seam. Sew it with right sides together, starting and finishing at the hems, and then flat fell it:

1. Trim one seam allowance to 1/4 inch and leave the other at 1/2 inch.
2. Press the wider allowance over the trimmed one, so the raw edge is enclosed.
3. Press the fold so it sits flat against the leg.
4. Stitch close to the folded edge, 1/8 inch in, from hem to hem.
5. Turn the piece over and stitch a second row 1/4 inch from the first, so the seam has two visible lines.

Side seams are easier and can take either a flat fell or a simple pressed open seam with the edges finished by zigzag. A French seam is the best choice on lawn and voile, where the fabric is too light for a flat fell to sit flat. There are other options in this round-up of ways to finish raw edges of fabric if the machine in front of you cannot do a flat fell cleanly. Try the shorts on at this point, before the waistband goes on: pin the centre front closed, sit down, and check the crotch and the seat. Adjusting the side seams now takes ten minutes, and adjusting them after the casing is sewn takes an hour.

Step 8: Insert the Elastic Waistband

The casing goes on before the elastic, and its depth is set by the elastic width plus 1/4 inch of clearance. For 1 inch elastic, press the top edge under by 1/2 inch, then press again by 1 1/4 inches, and stitch around the lower fold, leaving a 2 inch gap in the back for threading.

The elastic length is the number that decides comfort: cut it 3 to 4 inches shorter than the waist, so 30 to 31 inches for a 34 inch waist. Use a safety pin to thread it through, overlap the ends by 1 inch, and zigzag across the overlap twice before letting the casing close.

The third option, a separate band sewn to the waist and turned to the inside, gives the neatest result and takes the longest. The second, where the elastic is zigzagged to the waist edge and then folded over, is the one to use if threading a safety pin through a casing has defeated you before. Either way, stitch through the casing at the side seams to stop the elastic rolling, which is the failure the table at the top of this guide warns about.

The first try on is the moment to check the elastic tension. If the waistband digs in, unpick a little of the casing and swap to a longer length; if it gapes, shorten it by 1 inch. Doing this before the hem is sewn means the pair gets adjusted while it is still easy to handle.

Step 9: Hem the Legs

Press the hem before sewing it, in two passes: 1/2 inch to the inside, then another 1/2 inch on top of that. Pressing, rather than pinning, is what keeps the second fold even all the way round, because a hem that wanders by 1/8 inch at the side seam is visible from across a room.

1. Turn the hem up 1/2 inch and press all the way around the leg opening.
2. Turn it up another 1/2 inch and press again, so the raw edge is enclosed.
3. Pin at the inside leg seam and at both side points, then every 2 inches between them.
4. Stitch 1/8 inch inside the upper fold, with a 2.5 mm stitch length.
5. Backstitch at the start and finish, then press the hem flat from the wrong side.

The order of the legs matters: hem both before the waistband is finished if the elastic method allows it, because a hemmed leg opening is easier to press while the shorts still lie flat. On very light cotton, a 5/8 inch double fold is enough and sits better than a full inch.

Step 10: Press, Check and Add the Button

Press every seam once more, from the wrong side, with the seam allowances opened. Then press the fly flat, the waistband flat, and the hems flat, and hang the shorts for ten minutes so the fabric cools in shape rather than being folded warm.

1. Check the fly opens and closes without the topstitching puckering.
2. Mark the button position through the buttonhole, with the shorts done up, rather than measuring down from the waist.
3. Sew a 4 hole button with a thread shank, so the fabric has room to sit under it.
4. Check both hems are level by folding the shorts in half and matching the inside leg seams.
5. Snip any loose threads, press once more, and wash the shorts before wearing them.

The guide to sewing a pair of trousers covers the same fly and waistband sequence at full length, and is worth reading once the shorts are done, because the construction logic carries straight over to a longer leg. A dress with an elastic waist uses the identical casing technique, which is why the empire waist dress tutorial is a good next project for the casing practice.

Boxer Shorts Size and Elastic Chart

Common Mistakes That Ruin the Fit

The most expensive mistake is cutting the fabric before checking the side seam lengths, because there is no recovery. The second is cutting the elastic to the exact waist measurement, which produces a pair that will not stay up, and the third is skipping the press between steps, which shows in every topstitched line on the garment.

Troubleshooting a Pair That Does Not Fit

How to Care for Handmade Boxer Shorts

Wash handmade cotton boxers inside out at 30 degrees, with a low spin, and skip the dryer. The seams are the first thing to go in a hot dryer, because the flat felled edge shrinks at a different rate from the seam it wraps, and the elastic loses recovery at temperatures a cotton cycle reaches easily.

Pre-wash the fabric before the first pair, not after. Cotton shrinks 3 to 5 percent on the first hot wash, and a pair cut from unwashed fabric will come out of the machine one size smaller than the pattern, which is the last of the mistakes in the table above and the easiest one to avoid.

Frequently Asked Questions

Conclusion

A pair of handmade boxer shorts is really four numbers, one seam allowance and a sequence: draft from the hip, keep the side seams matched, flat fell the inside leg, and cut the elastic shorter than instinct says. Get those right and the ten steps above run in under two hours and survive the first fifty washes.

In Mithu’s experience teaching this project, the people who come back with a second pair are the ones who wrote their measurements on the pattern pieces and kept them. The pattern gets better every time: an eighth of an inch off the back crotch extension, half an inch off the hem, a deeper casing for wider elastic, and by the third pair it fits like something bought.

Start with a cheap cotton, make the first pair without a fly, and let the pattern prove itself before you cut into the good flannel. The guide to finishing raw edges is the other page worth keeping open beside the machine while the first pair is under the needle.

So what is stopping you from cutting the first pair this weekend?

About This Guide

This guide was tested by Mithu, who drafted the front and back pieces from the worked example, sewed three pairs in cotton poplin and flannel, and measured the elastic at 30 to 31 inches for a 34 inch waist. The crotch curve and the raised back waist were the two drafting changes that made the biggest difference to comfort. Numbers are given for a 40 inch hip and scale with the tables above.

All images in this article were created using AI.