A buttonhole is a deliberate gap you create in your knitted fabric by binding off stitches, then casting new ones back on in the same row

The most common method is the one-row buttonhole, which works for most garments. You knit to the spot where you want the hole, bind off a small number of stitches (usually 2 to 4, depending on your button size), then cast those stitches back on using the cable cast-on or another method. The result is a small opening that your button will pass through. The process takes one row and creates a neat, finished edge without extra steps.

Buttonholes need to match your button size—too small and the button won't fit, too large and it will slip through. A good rule is to bind off as many stitches as your button is wide, measured in stitches. Test this on a swatch if you are unsure.

Key Takeaways

  • The one-row buttonhole is the fastest method: bind off stitches on one row, cast them back on, and continue knitting.
  • Bind off the same number of stitches as your button is wide to may support a proper fit.
  • Use the cable cast-on or backward loop cast-on to replace the bound-off stitches so the edge stays neat.
  • Plan buttonhole placement before you start knitting by marking the rows where each hole should go.
  • A two-row buttonhole (binding off on one row and casting on the next) creates a reinforced edge and works well for heavy fabrics.

How to work a one-row buttonhole step by step

Knit to the position where your buttonhole should start. This is the point where your button will sit when the garment is buttoned. Count your stitches carefully so you land in the right spot—measure from your edge or use stitch markers to guide you.

Bind off the number of stitches your button needs. If your button is roughly the width of 3 stitches, bind off 3 stitches using your normal bind-off method (knit one, pass the first stitch over the second, and repeat). Stop when you have bound off the correct number and still have one live stitch on your right needle.

Cast the stitches back on using the cable cast-on. Insert your needle under the loop on your right needle, then use the working yarn to create new stitches until you have replaced all the ones you bound off. This method creates a neat, finished edge that matches the rest of your fabric. If you prefer, the backward loop cast-on also works, though it is slightly less sturdy.

Continue knitting the rest of the row as normal. The buttonhole is complete. On the next row, you will knit across the new stitches just as you would any others.

Choosing the right buttonhole for your fabric weight

Lightweight fabrics like fingering-weight yarn work well with a one-row buttonhole because the fabric is dense enough to hold the button without extra reinforcement. The single row of new stitches is sufficient, and the buttonhole will not stretch or sag over time.

Heavier fabrics and garments that will see heavy use—cardigans, coats, or sweaters made from bulky yarn—benefit from a two-row buttonhole. Bind off your stitches on one row, then on the very next row, cast them back on. This creates a reinforced edge and prevents the buttonhole from stretching. The extra row also gives you a chance to adjust the tension if your first row felt loose.

For very stretchy or delicate fabrics, consider a yarn-over buttonhole instead. This method uses a yarn-over decrease (yarn over, then knit two together) and creates a small eyelet. It is less sturdy than binding off, but it is reversible and works well for lace or shawls where a traditional buttonhole would look out of place.

Planning buttonhole placement before you knit

Measure your finished garment and mark where each button should sit. For a cardigan, buttons usually go every 3 to 4 inches vertically, starting about 1 inch from the bottom edge. Mark these positions on your pattern or on a piece of paper so you know exactly which row to work each buttonhole.

Count the rows between buttonholes and write them down. If your first buttonhole is on row 20 and your second is on row 50, you know you need to knit 30 rows between them. This prevents mistakes and keeps your buttonholes evenly spaced.

Place the first buttonhole slightly higher than the bottom edge of your garment—usually 1 to 1.5 inches up—so the button sits on the body of the piece rather than at the very edge. The last buttonhole should be at least 1 inch below the neckline to avoid interfering with neck shaping.

Finishing the edges of your buttonholes

A one-row buttonhole with a cable cast-on needs no additional finishing. The cast-on edge is already neat and will not unravel. However, if you notice the edges feel loose or the hole is slightly larger than you intended, you can tighten it by weaving in the yarn tails carefully with a tapestry needle.

If you used a backward loop cast-on and the edge feels unstable, you can reinforce it after blocking. Thread a tapestry needle with matching yarn and make a small stitch along the cast-on edge, catching just the outer loop of each new stitch. This takes a few minutes per buttonhole but adds durability, especially on cardigans that will be buttoned and unbuttoned frequently.

Block your finished garment before sewing on buttons. Blocking opens up the stitches and evens out the buttonhole edges, making them look more polished and ensuring they are the correct size.

Common mistakes and how to avoid them

Binding off too many or too few stitches is the most common error. If your button falls through, you bound off too few. If the button is too tight, you bound off too many. Test your buttonhole size on a swatch before committing to your garment. Knit a small square, work a one-row buttonhole in the middle, and try your button in it. Adjust the number of bound-off stitches if needed.

Casting on too loosely after binding off creates a gap that is larger than intended and looks sloppy. Use the cable cast-on and keep your tension firm—not tight, but consistent with the rest of your knitting. If you struggle with this, practice on a swatch a few times before working buttonholes on your actual garment.

Forgetting to mark buttonhole positions before you start is frustrating because you may knit past the row where a buttonhole should go. Write down the row numbers or use stitch markers to flag the rows where each buttonhole belongs. Check your pattern or your notes every few rows to stay on track.

Frequently Asked Questions

How do I know how many stitches to bind off for my button?

Measure your button's width in stitches by laying it across your gauge swatch. If your button spans 3 stitches, bind off 3. Test on a swatch first—it is easier to adjust before you commit to your garment. A button that is slightly loose is better than one that is too tight.

Can I make a buttonhole on a purl row?

Yes. The process is identical: bind off stitches on the purl row, then cast them back on using the cable cast-on or another method. The buttonhole will look the same on both sides of the fabric.

What if I made a buttonhole in the wrong place?

If you caught the mistake within a few rows, you can unravel back to that row and redo it. If the garment is nearly finished, you can cut the buttonhole out and pick up the stitches around it, then bind them off neatly. This is more advanced, so practice on a swatch first if you have not done it before.

Do I need to reinforce buttonholes on a sweater I will wear often?

For everyday cardigans, a two-row buttonhole or a reinforced one-row buttonhole is worth the extra time. The buttonhole will hold up better to repeated buttoning and unbuttoning. For a garment you wear occasionally, a standard one-row buttonhole is fine.