KFB creates two stitches from one by knitting into the front and back of the same loop

KFB stands for "knit front and back" and is one of the most common ways to add stitches to your work. Instead of dropping the loop off your needle after you knit it, you knit the same loop twice — once through the front and once through the back — then slip it off. You end up with two stitches where you had one.

The result is a small hole or bump on your fabric, depending on how tight you work it. KFB is visible in the finished piece, so it works best in projects where that texture is intentional or won't show — like the underside of a sleeve, the inside of a hat, or a decorative increase in lace patterns. If you need an invisible increase, other methods like M1 (make one) exist, but KFB is faster and requires no setup.

You'll see KFB written in patterns as "kfb" or sometimes just "K1fb". It's worked on knit rows (right-side rows in stockinette stitch) and increases one stitch per occurrence.

Key Takeaways

  • KFB means knitting into the front loop of a stitch, then knitting into the back loop of the same stitch before dropping it off the needle.
  • The increase creates a visible bump or hole in your fabric, making it suitable for textured or decorative projects rather than seamless shaping.
  • KFB is faster than other increase methods because it requires no yarn manipulation or setup before the stitch.
  • The stitch should be worked loosely enough that you can access both the front and back loops without splitting the yarn.

Step-by-step: How to work a KFB increase

Insert your right needle through the front of the next stitch on your left needle, from left to right, the way you normally knit. Wrap your yarn around the right needle and pull through to create a new loop. Do not drop the stitch off the left needle yet — this is the key difference from a regular knit stitch.

Now insert your right needle through the back of that same stitch, from right to left (going behind the stitch). Wrap your yarn around the right needle again and pull through. Now drop the original stitch off the left needle. You now have two stitches on your right needle where you started with one.

The whole motion takes about two seconds once you've done it a few times. The most common mistake is dropping the stitch too early or inserting the needle into the back loop incorrectly. If you're struggling to access the back loop, your stitches may be too tight — try loosening your tension slightly on the first knit into the front.

Where KFB appears in patterns and projects

KFB shows up most often in shaping that doesn't need to be invisible. Sweater sleeves increased with KFB at the edges will have a small line of bumps running up the seam, which is hidden when you sew the sleeve together. Hat crowns often use KFB increases because the texture blends into the overall fabric once the hat is worn.

In lace and textured patterns, KFB is sometimes used deliberately for visual effect. A pattern might call for KFB increases in specific spots to create a decorative line or to add stitches in a way that looks intentional rather than hidden. Always check your pattern to see whether the increase should be visible or not — if the pattern doesn't specify which increase method to use, KFB is usually safe.

Patterns written for beginners often call for KFB because it's the easiest increase to learn. More advanced patterns may ask for M1L (make one left) or M1R (make one right) when the increase needs to be invisible or to lean in a specific direction.

Common mistakes and how to fix them

The most frequent error is knitting into the front loop, then accidentally knitting into the front loop again instead of the back. This happens when you don't rotate your needle or when the stitch sits in an awkward position. The fix is to slow down and consciously insert your needle from the opposite direction the second time.

Another common issue is splitting the yarn — inserting your needle through the middle of the stitch rather than cleanly through the loop. This creates a weak stitch and makes the increase look messy. If this happens, make sure you're inserting the needle all the way through the loop before wrapping yarn, and that your working yarn isn't in the way of the needle.

Some knitters drop the stitch too early and end up with only one stitch instead of two. The stitch must stay on the left needle until you've completed both the front and back knits. If you've already dropped it, you'll need to pick it back up with your left needle and try again.

KFB versus other increase methods

M1 (make one) is the most common alternative to KFB. M1 creates an invisible increase by picking up the horizontal strand between two stitches and knitting into it. It takes slightly longer than KFB and requires you to identify that strand, but the result is seamless. Use M1 when your pattern calls for invisible shaping or when you're increasing in the middle of a row where a visible bump would look out of place.

YO (yarn over) is another increase, but it creates a hole rather than a solid stitch. It's used in lace patterns where the hole is part of the design. YO is faster than KFB but only works in specific contexts.

Lifted increases (knitting into the stitch below) are less common but create a nearly invisible increase. They're slower than KFB and require more precision. Most patterns will tell you which increase to use, but if you're substituting methods, KFB is a safe choice for any project where visibility doesn't matter.

Tension and consistency when working KFB

KFB stitches often come out slightly looser than regular knit stitches because you're working twice into the same loop. To keep your fabric even, try to knit the back loop slightly tighter than the front loop. Some knitters find it helpful to knit the front loop normally, then deliberately tighten the yarn slightly before inserting the needle into the back.

If your KFB increases are noticeably looser than the rest of your fabric, you may be pulling the yarn too loosely after the first knit. The yarn should be snug against the needle but not so tight that you can't insert the needle into the back loop. This balance comes with practice — after a few rows of increases, your tension will even out.

Consistency matters more than perfection. If all your KFB stitches look the same, even if they're slightly looser than the surrounding fabric, your project will look intentional and finished. Uneven increases are more noticeable than slightly loose ones.

Frequently Asked Questions

Can I use KFB on purl rows?

Yes. On a purl row, you would purl into the front loop, then purl into the back loop of the same stitch before dropping it. The motion is the same as KFB on a knit row, just using the purl stitch instead. This is sometimes written as PFB (purl front and back) in patterns.

What if I can't fit my needle into the back loop?

Your stitches are likely too tight. Try loosening your tension on the first knit into the front, or make sure you're inserting the needle all the way through the loop before wrapping yarn. If the stitch is still too tight, you may need to go up a needle size for your increases only, then return to your regular size for the next row.

Does KFB always create a visible hole?

Not always. A tight KFB creates more of a bump than a hole, while a loose KFB creates a more obvious hole. The visibility also depends on your yarn weight and stitch pattern. In textured or dark yarns, KFB is less noticeable than in smooth or light-colored yarn.

Can I use KFB for decreasing stitches?

No. KFB only increases stitches. To decrease, you would use K2tog (knit two together), SSK (slip, slip, knit), or P2tog (purl two together), depending on your pattern and the direction you want the decrease to lean.

How many stitches should I increase per row with KFB?

That depends on your pattern. Some patterns call for KFB in every stitch across a row (doubling your stitch count), while others ask for KFB every few stitches or only in specific spots. Always follow your pattern's instructions for where and how often to use KFB.