How to Sew a Buttonhole on a Sewing Machine
Machine buttonholes are strong, neat, and much faster than hand-worked ones once you know the settings. This guide takes you from testing on a scrap to cutting a clean opening without slicing through the bartacks.
Materials
- Fabric
- Fusible interfacing
- Buttons
- All-purpose thread
Tools
- Sewing machine with buttonhole function
- Buttonhole foot
- Seam ripper
- Fabric marker or chalk
- Small sharp scissors and a pin
Steps
- 01
Test on an interfaced scrap
Interface a scrap of the same fabric with the same stabiliser you will use on the garment, then sew a test buttonhole. Machine buttonholes behave differently on every fabric, so the test is the only way to know your settings.
- 02
Mark the placement
Mark the buttonhole position on the fabric with chalk or a washable pen, running the line along the direction the button will travel. Add the buttonholes before you attach the facing or lining if your pattern calls for it.
- 03
Set the length and width
Set the buttonhole length about 3 mm longer than the button diameter plus its thickness, and set the width to suit the thread and button. Use the buttonhole foot gauge or the machine dial to lock in the size.
- 04
Attach the buttonhole foot
Fit the buttonhole foot and slide the fabric under it with the marked line centred. Most machines sew the buttonhole automatically; if yours works in stages, follow the order of bartack, side, bartack, side.
- 05
Sew the buttonhole
Lower the needle at the start mark and sew at a slow, even speed, letting the foot feed the fabric. Stop when the machine finishes the sequence and raise the needle before lifting the foot.
- 06
Cut the opening
Place a pin across each end of the buttonhole to stop the seam ripper, then cut from each end toward the centre. Cut along the middle of the opening without nicking the bartacks, and trim any loose threads.
What Each Part of the Finished Buttonhole Is Doing
A machine buttonhole is really four pieces of stitching: a bartack at each end and a satin-stitch column down each side. The bartacks do the load-bearing work. The button presses against them every time the garment is fastened and unfastened, so they are stitched densely enough that the bars sit almost on top of one another, and they are what stops the cut from running past the ends of the opening. That is the structural reason the pin-and-cut instructions exist: a nick through the bartack takes out the anchor, and the slot then frays open from that end.
The two side columns are the part that actually seals the raw edge. On every pass the needle swings out past the cut and comes back, so the thread wraps over the loose warp and weft ends and pins them under a column of stitching. Width does a structural job here, not just a decorative one: a narrow column covers less of the cut edge and wears through sooner on a placket that gets opened all day, while a wide one builds a heavier ladder of thread that stiffens the fabric around the button. Set the width to suit the thread and the button, then let the test scrap tell you whether this fabric can carry it.
The length setting does the second structural job. The slot between the bartacks has to be longer than the button's diameter by roughly the amount of space the button's own thickness eats up as it tips through, which is where the extra 3 mm comes from: a flat button needs almost none of it, a domed or thick button needs all of it. Set it too short and the button will not pass without forcing, which is the quickest way to break a bartack; set it too long and the button rides in a loose slot and the front gapes.
The direction the marked line runs is not cosmetic either. When the garment is worn, the button is dragged sideways across the body, so a buttonhole whose long axis follows that drag puts the load onto the bartack, where the stitching is strongest. Turn the same buttonhole 90 degrees and the pull acts across the slot instead: the sides part, the button slips out, and the buttonhole looks perfectly neat until the garment is actually worn.
Common Buttonhole Failures and How to Read Them
The most common casualty is the nicked bartack. Check for it by holding the finished buttonhole up against a light and following the bar at each end to see that it is continuous, then feel along it with a fingertip for a break. If only a few threads are cut, a small dab of fray check or seam sealant will hold it and stop the fray. If the bar has been cut clean through so the opening has no end, the strongest repair is to re-stitch the buttonhole on top of the old one with exactly the same settings, so the new bartacks land over the damaged ones — do not try to move the buttonhole, because the button is already placed to match it.
A puckered or corded buttonhole is the other frequent complaint: the fabric between the columns lifts into a ridge, or the whole buttonhole cups and stands away from the cloth. Read it by location. A ridge running along the whole buttonhole points at the setting — density or width too high for the fabric, or the upper tension too tight. A ridge or a wobbly column at one end only usually means the fabric was steered or pulled while the foot was feeding. Either way, fix it on the scrap before you touch the garment: back off the width a step, loosen the upper tension a notch, and let the feed dogs move the fabric with your hands only guiding.
On a loose or spongy weave the columns can sink instead of sitting on top, and the buttonhole reads as a fuzzy dent rather than a stitched bar. That is not a tension problem — the needle is pushing the weave apart instead of piercing it. The fix is more stabiliser, not more thread: a second layer of fusible or a slightly heavier weight, plus a fresh needle. Test both changes on the same scrap before committing them to the garment.
Order is the quiet failure. Cut every buttonhole only after the whole set is sewn, so one bad buttonhole does not leave you short of fabric with the rest of the placket still to do. And mark and stitch them before the facing or lining goes on if your pattern asks for it, when the layer still lies flat, the marking line is visible, and the buttonhole foot has room to travel.
Interfacing, Thread, and Tools: What Changes When You Substitute
Fusible interfacing is the default because it holds the weave firm while the needle works, and its weight changes the result more than most people expect. A lightweight fusible keeps a shirt placket buttonhole crisp and flat; a mid-weight one supports a bigger button on a jacket front; too heavy and the buttonhole stands off the cloth like a plastic card, and the bartacks look like beads. If the fabric is heat sensitive — velvet, coated cloth, seersucker, some synthetics — a fusible can scorch the surface or flatten the pile, so substitute a sew-in interfacing or a strip of silk organza. It stabilises without heat, but you must baste it in place first, because a sew-in that shifts while you stitch gives you a wandering, uneven column.
All-purpose polyester thread is not just the default, it is the right answer, because the bartack is the most rubbed stitching on the whole garment. Polyester flexes with the fabric in the wash and outlasts the abrasion that cotton thread loses to. Match the thread to the fabric to make the buttonhole disappear, or choose a deliberate contrast to turn it into a design detail. Heavier buttonhole twist or topstitching thread fills the column and looks intentional, but it also wants a wider width setting and a larger needle, and it will not sit neatly in a fine fabric. Shiny rayon or embroidery thread flatters a decorative buttonhole but is weaker exactly where you need strength.
The needle decides whether the buttonhole sits on the cloth or in it. Size it to the fabric, and change it the moment it starts popping or snagging — a dull needle pushes the weave apart around the buttonhole, which makes fraying worse rather than better. On a very fine or slippery fabric, a strip of tear-away or water-soluble stabiliser placed under the buttonhole is a useful substitute for a fusible: stitch over it, then tear or rinse it away, and the buttonhole keeps its shape without any heat at all.
Tools matter at the cutting stage. The gauge on the buttonhole foot is a starting point, not an answer — always check the setting against the actual button, because two buttons sold as the same size can differ in thickness. For a full set on denim, wool, or a multilayer placket, a buttonhole chisel and block cuts a cleaner slot than a seam ripper that has to be dragged through the cloth, and a tailor's awl opens an eyelet without cutting anything. Keep fray check or seam sealant within reach for slippery fabrics, and never cut with a dull ripper blade — the force it needs is exactly what makes it jump into a bartack.
Keyhole, Corded, and Bound: Adapting the Same Setup
The keyhole buttonhole is a straight slot with a round eyelet at one end. The eyelet is what makes it worth switching: a thick button shank passes through the round opening instead of straining a straight slot, so the buttonhole holds better under load and the button sits more squarely. It is the version to use on coats, heavier fabrics and thick buttons, and it is usually set with a slightly shorter slot than a straight buttonhole because the eyelet supplies the extra room. If your machine has the stitch, select it; if it does not, a straight buttonhole with one end carefully opened with an awl gets close.
For a raised, hand-worked look, try a corded buttonhole: lay a strand of heavier thread or gimp under the buttonhole foot, stitch the buttonhole over it, then pull the ends so the cord is drawn up inside the side columns. This reinforces the buttonhole as well as lifting it, because the cord takes the wear along the edges instead of the stitching alone. It looks especially right on wool, tweed and tailored coats, and it is the simplest way to make a machine buttonhole read as a hand-worked one.
The bound buttonhole, also called a welt, uses no machine buttonhole stitch at all — the slot is built from two strips of fabric, with the ends mitred and the facing slashed behind it afterwards. It is the most formal option and the one to choose where a stitched buttonhole would look wrong: fine woollens, tailored jackets, any cloth where a line of thread across the front would break the surface. It takes more steps and some practice to get the two lips even, so treat it as its own project rather than a small variation.
Where you stop on that ladder should depend on how the plain buttonhole is going. Stay with the standard version until you can sew a whole set with even columns without stopping to inspect each one; add the corded version once your tension is steady enough that you are not fighting puckers; and save the bound buttonhole for when a straight buttonhole on the test scrap comes out right the first time.
Pressing, Cutting Order, and Care So the Buttonholes Last
Press the finished buttonholes from the wrong side, with a pin laid across each end so the buttonhole cannot stretch open under steam, and ideally over a pressing block or a rolled towel so the stitching is not flattened into the cloth. Use a press cloth and moderate heat: polyester thread glazes and loses its shape at high iron temperatures, and a glazed column stays flat and shiny for the life of the garment. If you have dabbed fray check on the cut ends, let it dry completely before you press.
Cut only after the whole set is stitched, use a fresh blade in the seam ripper, keep the pin across each end, and cut from each end toward the centre. That order protects everything you have already sewn: a single bad buttonhole found before any cutting can be re-stitched over, but one discovered after the rest of the placket has been opened usually cannot.
In the wash, fasten the front before the garment goes in, so the buttonholes are not stretched and dragged open, and do not lift a wet garment by a single buttoned front — the buttonholes end up carrying the whole weight of the wet cloth. Air-dry rather than tumble-drying on high heat, and if you press the garment afterwards, keep the iron off the buttonhole itself and let it cool flat before the button goes back through.
Finally, look at the bartacks now and then. Fuzz, a paler patch of thread, or a loose thread end means the buttonhole is wearing; a loose end can be dabbed with fray check, and a bartack that has worked loose can be re-stitched by sewing the same buttonhole on top of the old one at the same settings so the new stitching lines up. The overall test is simple: every button should pass through with a firm push and sit without gaping. Gap means the slot was cut too long or the fabric was not stabilised enough; too tight means the length setting was short of the button's diameter plus its thickness plus that 3 mm.
Frequently asked questions
- How exactly do I work out the buttonhole length?
- Measure the button across its widest point, add the thickness of the button, then add about 3 mm. A button that is 12 mm wide and stands 3 mm tall therefore gets an 18 mm setting. Set it on the buttonhole foot gauge or the machine dial, sew the test on the interfaced scrap, and try the real button in it: it should pass through with a firm push and sit without gaping. If it is tight, add a millimetre at a time; if the button slides around in the slot, shorten it the same way.
- Do I really need the interfacing — what happens if I skip it?
- Yes. The fusible is what gives the needle something firm to stitch into. Without it, the needle pushes the weave apart instead of piercing it, the side columns sink into the fabric, and the bartacks pull out the first time the button is used hard. On a very light fabric use a second layer of lightweight fusible rather than a heavier one, so the buttonhole stays crisp without going stiff. On velvet, coated cloth, seersucker or another heat-sensitive fabric, swap the fusible for a sew-in interfacing or a strip of silk organza basted in place — and test the interfacing on the same scrap you use for the test buttonhole, since the two things are decided together.
- I cut through one of the bartacks with my seam ripper. Can I save it?
- If only a few threads are broken, dab a little fray check or seam sealant on the cut end and let it dry — that usually stops it fraying further. If the bar is cut clean through so the opening has no end, the strongest fix is to re-stitch the buttonhole directly on top of the old one with the same length and width settings, so the new bartacks land over the damaged ones; do not shift the position, because the button is already placed to match it. Next time, place a pin across each end of the buttonhole before you cut and cut from each end toward the middle, so the blade meets the pin instead of the bartack, and use a sharp blade — a dull one needs force and that is when it jumps.
- My pattern says to sew the buttonholes before the facing or lining. Why does the order matter?
- Because the buttonhole foot needs the layer flat and the marking line visible. Once a facing or lining is attached, the foot has to ride over a step in the fabric, the marked line is buried underneath, and you can no longer see what you are stitching. If your pattern calls for the buttonholes first, follow it, and sew the whole set before cutting any open. If the garment is already assembled, you will have to fold the facing out of the way, stitch the buttonhole through the outer layer only, and then deal with the facing behind the opening by hand — workable, but far slower and much easier to get wrong.