What KFB means and why you use it

KFB stands for "knit front and back," and it is an increase that turns one stitch into two stitches. You knit into the front loop of a stitch the normal way, then before you drop that stitch off the left needle, you knit into the back loop of the same stitch. This creates two new stitches on the right needle where there was one before.

You use KFB when a pattern tells you to increase — usually written as "kfb" in the instructions. It is one of the most common increases in knitting because it is fast, creates a small hole or texture on the fabric, and sits at the edge of your work or scattered across a row depending on where the pattern places it.

Key Takeaways

  • KFB means knitting into both the front and back loop of the same stitch before dropping it off the left needle.
  • The stitch creates a visible increase that leaves a small hole or bump in the fabric, which is often intentional in lace or textured patterns.
  • You perform KFB on the right needle while the original stitch is still on the left needle.
  • KFB increases one stitch per occurrence, so doing it multiple times across a row increases your stitch count by that many stitches.

Step-by-step: How to perform KFB

Start with your working yarn in the back and your needles in the ready position — left needle holding the stitches you are about to work, right needle empty or holding completed stitches. Insert your right needle through the front of the next stitch on the left needle from left to right, the way you would for a normal knit stitch.

Wrap your working yarn around the right needle and pull it through to create a new stitch on the right needle. Do not drop the original stitch off the left needle yet — this is the key difference from a regular knit stitch. Instead, insert your right needle through the back loop of that same stitch (from right to left this time, going behind the stitch). Wrap the yarn around the right needle again and pull through to create a second new stitch.

Now drop the original stitch off the left needle. You have completed one KFB: one stitch has become two. Continue with your next stitch as normal. The two new stitches sit on your right needle, and you will work them as separate stitches in the next row.

Where KFB sits in your fabric and what it looks like

KFB creates a small hole or a visible bump on the right side of your work, depending on your yarn and tension. In lace patterns, this hole is intentional and part of the design. In other patterns — like shaping for sleeves or increases in the middle of stockinette — the bump may be less visible or you may choose a different increase to hide it better.

The increase always leans slightly to the right because of how the back loop is worked. If you are increasing on both sides of a piece (like shaping a sleeve), you might use KFB on one side and a different increase like YO (yarn over) or M1 (make one) on the other side to keep the edges balanced and symmetrical.

KFB versus other common increases

A yarn over (YO) is faster and creates a deliberate hole, which is why it appears in lace patterns. You straightforward bring the yarn to the front, then knit the next stitch, and the yarn over counts as a new stitch. It is more visible than KFB and always leaves a hole.

A make one (M1) is worked between two stitches rather than into a stitch itself. You pick up the horizontal strand between stitches and knit into it. M1 is nearly invisible and is the best choice when you want an increase that does not show. It takes slightly longer than KFB because you have to locate and lift the strand.

KFB sits in the middle: it is quick, it creates a small texture or hole, and it is worked directly into a stitch. Use it when your pattern calls for it, or when you want a visible increase that is faster than M1 but less dramatic than YO.

Common mistakes when learning KFB

The most common error is dropping the original stitch off the left needle too early — after the first loop but before the second. This leaves you with only one new stitch instead of two, and your increase does not happen. Keep the stitch on the left needle until you have completed both the front and back loops.

Another mistake is twisting the back loop. When you insert your needle through the back of the stitch, make sure you are going through the actual loop, not around it or under it. If the back loop feels tight or awkward, you may be in the wrong place. The back loop is the one closest to the tip of your left needle.

Tension can also be uneven after KFB, especially the stitch right after the increase. The two new stitches may be looser than the rest of your row. This evens out as you work more rows, but if it bothers you, you can knit the two new stitches slightly tighter on the next row.

Reading patterns that use KFB

When you see "kfb" in a pattern, it usually appears in a row instruction like "K2, kfb, K4, kfb, K2" — meaning knit 2 stitches, then increase one stitch with KFB, then knit 4 stitches, then increase again, and so on. Each kfb adds one stitch to your total count for that row.

If a pattern says "kfb in each stitch across," you perform KFB on every single stitch in the row, which doubles your stitch count. This is common in patterns that expand quickly, like the crown of a hat or the center of a circular shawl. After a row of kfb in each stitch, your needle will feel very full.

Frequently Asked Questions

Does KFB create a hole in the fabric?

KFB creates a small hole or visible bump, depending on your yarn weight and tension. In lace patterns, this is intentional. In other patterns, the hole may be barely noticeable. If you want an increase with no visible hole, use M1 (make one) instead.

Can I use KFB on the edge of my work?

Yes, KFB works well at the edges for shaping sleeves or necklines. The increase sits right at the edge stitch, making it straightforward to count and repeat on both sides of a piece. Many patterns use KFB at the beginning or end of a row for this reason.

What if I accidentally knit into the back loop first instead of the front?

The order does not matter much — you will still end up with two stitches. The stitch may twist slightly differently, but the increase works the same way. Most knitters work front first straightforward because it feels more natural, but back first is not wrong.

How do I fix a KFB mistake if I notice it several rows later?

If you missed a KFB and created only one stitch instead of two, you can pick up that stitch and knit into it on the next row to create the second stitch. If you created two stitches when you should have created one, you can decrease on the next row using K2tog or SSK to remove the extra stitch.