A buttonhole is a deliberate opening you create in your knitted fabric while you knit

A buttonhole is a small opening you make in your knitted piece—usually in a cardigan, sweater, or jacket—so a button can pass through it. You create it by binding off a few stitches in one row, then casting new stitches back on in the next row. The result is a neat, finished hole that won't unravel.

The most common method is called the one-row buttonhole or yarn-over buttonhole, and it takes just two rows to complete. You can also make a two-row buttonhole if you want a sturdier opening. Both methods work on stockinette stitch (the smooth, V-patterned fabric most cardigans use) and on ribbed edges.

Key Takeaways

  • The one-row buttonhole is the fastest method: you bind off stitches on one row, then cast them back on in the next row.
  • Plan buttonhole placement before you start knitting by measuring your button size and spacing them evenly along the edge.
  • A buttonhole should be roughly the same width as your button's diameter, usually two to four stitches wide.
  • Test your buttonhole size on a scrap of yarn before you commit to your finished piece.

Measure and mark your buttonhole positions before you knit

Before you start, decide how many buttons you need and where they should sit. Measure your button's diameter—this tells you how wide your buttonhole needs to be. A typical button is about half an inch to three-quarters of an inch across, which usually means binding off two to four stitches per buttonhole.

Space your buttonholes evenly. If you are making a cardigan with five buttons, place the top button about one inch below the neckline, the bottom button about one inch above the hem, and space the remaining three evenly between them. Write down which row each buttonhole should start on, or use stitch markers to mark the spot as you knit.

If your pattern includes buttonhole instructions, follow those instead—they are designed for that specific garment's fit and button size.

The one-row buttonhole method: bind off and cast on

When you reach the row where your buttonhole should go, knit to the spot where the hole begins. Stop and count: you are about to bind off the same number of stitches as your buttonhole width. If your buttonhole is three stitches wide, you will bind off three stitches.

Bind off those stitches using your normal bind-off technique (knit two stitches, pass the first over the second, and repeat). When you have bound off the correct number, cut the yarn and pull it through the last stitch to find it. You now have a gap in your knitting.

On the very next row, when you reach that gap, you need to cast new stitches back on to close it. Use the cable cast-on or backward-loop cast-on method to add the same number of stitches you bound off. If you bound off three, cast on three. Knit the rest of the row as normal. The buttonhole is complete.

The two-row buttonhole for a sturdier opening

If you want a buttonhole that feels more solid and less stretchy, use the two-row method. On the first row, knit to your buttonhole spot and bind off the required number of stitches. Finish the row normally. Do not cast anything back on yet.

On the second row, knit to the gap. Cast on the same number of stitches you bound off, using the cable cast-on method. Knit the rest of the row. The extra row of stitches creates a thicker, more durable edge around the hole.

Reinforce the edges if your buttonhole stretches

After you finish knitting and bind off all stitches, try your buttons in the holes. If a buttonhole feels loose or stretches too much, you can reinforce it with a needle and thread. Thread a tapestry needle with yarn that matches your knitting, and sew a small loop around the inside edge of the buttonhole, pulling gently to tighten it slightly. This is called buttonhole stitch and is purely optional—many knitters skip this step.

If a buttonhole is too small and your button will not fit, you have two choices: make the button hole larger by carefully cutting one or two extra stitches and securing the edges with sewing thread, or unravel back to that row and redo it wider. The second option is safer if you are new to knitting.

Practice on a test swatch first

Before you make buttonholes in your finished garment, knit a small swatch—about four inches square—in the same stitch and yarn you are using for your project. Make one or two practice buttonholes on it. This lets you see how your yarn and stitch pattern look with a hole, and whether your button size matches the opening you created.

A test swatch also shows you whether your buttonhole needs reinforcement or if it looks neat as-is. Once you are confident, you can move forward with your actual piece.

Common mistakes and how to avoid them

Buttonhole too small: You bound off fewer stitches than your button diameter requires. Measure your button again and count the stitches it spans when you hold it against your knitting. Add one more stitch to your bind-off if the button is a tight fit.

Buttonhole too loose: You cast on more stitches than you bound off, or your yarn is very stretchy. Make sure the number of cast-on stitches exactly matches the number you bound off. If looseness persists, use the reinforcement stitch described above.

Uneven buttonholes: You bound off a different number of stitches for each hole. Write down the exact number before you start, and count carefully each time.

Hole in the wrong place: You miscounted rows. Use stitch markers or a row counter to track which row you are on, and mark your buttonhole rows before you start knitting.

Frequently Asked Questions

Can I make a buttonhole on ribbed fabric?

Yes. On a rib (knit-purl pattern), bind off and cast on stitches the same way, but make sure you maintain the rib pattern on either side of the hole. If your rib is knit-two-purl-two, and your buttonhole falls on a knit section, bind off knit stitches and cast them back on as knits.

What if I want a horizontal buttonhole instead of a vertical one?

Horizontal buttonholes (which run left to right) use the same bind-off and cast-on method described here. Vertical buttonholes (which run top to bottom) require a different technique called yarn-over increases and decreases, and are more advanced. Start with horizontal buttonholes until you are comfortable with the basics.

How do I know if my buttonhole is the right size?

Your button should slide through with a little resistance—not so tight it strains the yarn, and not so loose it falls through on its own. If you are unsure, test it on your practice swatch. You can always make the next buttonhole slightly wider or narrower based on how the first one feels.

Do I need to sew around the buttonhole after I finish knitting?

No, it is optional. Many knitters leave buttonholes as-is and they look and function fine. Sewing around the edge (buttonhole stitch) is purely for reinforcement if the edges feel stretchy or if you want a more finished look.

What if I forgot to make a buttonhole and finished the whole garment?

You can cut a hole in the finished fabric and find the edges with sewing thread using buttonhole stitch. This is not ideal but works in a pinch. For future projects, mark buttonhole positions on your pattern before you cast on.