What KFB Means and Why You Use It
KFB stands for "knit front and back," and it is one of the most straightforward ways to add a new stitch to your needle. Instead of knitting once into a stitch and moving on, you knit into the same stitch twice—once through the front loop and once through the back loop—before sliding the old stitch off the needle. This creates two stitches where there was one, which is why knitters use it to increase.
You will see KFB in patterns that need a gradual, invisible increase. Because the new stitch sits right next to the original one, the increase blends into the fabric better than some other methods. It is common in shaping the sides of sweaters, widening the crown of a hat, or adding stitches in the middle of a row when a pattern calls for it.
Key Takeaways
- KFB means knitting into the front loop of a stitch, then the back loop of the same stitch, creating two stitches from one.
- Insert your needle through the front of the stitch as you normally would, wrap yarn, and pull the loop through without removing the old stitch.
- Insert your needle through the back loop of that same stitch, wrap yarn again, and pull through, then slide the original stitch off the needle.
- KFB creates a small bump or bar at the base of the increase, which is why patterns often use it in seam allowances or edge stitches where it will be less visible.
- The increase happens in the same row, so your stitch count rises when ready rather than waiting for the next row.
How to Perform KFB on a Knit Row
Start with your working yarn in back and your needles in the standard knitting position. Identify the stitch you want to increase into—usually the pattern will tell you which one, or you will be increasing into every stitch if you are widening an entire row.
Insert your right needle through the front loop of the stitch on your left needle, from left to right, exactly as you would for a regular knit stitch. Wrap your working yarn around the right needle and pull a new loop through to the front. Do not slide the original stitch off the left needle yet. This is the critical difference from a regular knit stitch—you are keeping the old stitch in place.
Now insert your right needle through the back loop of that same stitch. You will be going from right to left through the back of the loop. Wrap your yarn around the needle again and pull a new loop through. Now you can slide the original stitch off the left needle. You now have two new stitches on your right needle where one stitch used to be.
How to Perform KFB on a Purl Row
The mechanics are identical on a purl row, except your yarn starts in front and you work through the purl stitch instead. Insert your right needle through the front loop of the stitch on your left needle from right to left, as you would for a regular purl. Wrap yarn and pull a loop through, but leave the original stitch on the left needle.
Insert your right needle through the back loop of the same stitch from left to right. Wrap yarn and pull through. Slide the original stitch off. You have created two purl stitches from one, and the increase is complete.
Where the Increase Bar Appears and How to Hide It
When you use KFB, a small horizontal bar or bump appears at the base of the new stitch. This happens because you are working twice into the same stitch, and the yarn creates a visible line. In many patterns, this is not a problem—the bar sits in a seam allowance or at an edge where it will be hidden in finishing.
If you are increasing in the middle of a visible area and the bar bothers you, consider using a different increase method instead, such as a lifted increase or a yarn-over. However, for most everyday projects like sweater sleeves or hat shaping, the KFB bar is either invisible or so small that it blends into the fabric once the garment is worn.
Common Mistakes and How to Avoid Them
The most frequent error is sliding the original stitch off the needle too early. If you remove it after the first loop, you have only created one stitch instead of two, and your increase did not happen. Keep the old stitch on the left needle until you have completed both the front and back loops.
Another mistake is accidentally twisting the back loop. When you insert your needle through the back of the stitch, make sure you are going through the actual loop and not accidentally creating a twisted stitch. A twisted stitch will look uneven and can throw off your stitch count.
Some knitters also forget to wrap yarn on the second insertion. You must wrap and pull through twice—once for the front loop and once for the back loop. If you only wrap once, you will end up with a dropped stitch or a hole.
KFB in Different Stitch Patterns
In stockinette stitch (knit on the right side, purl on the wrong side), KFB is straightforward and the bar is usually hidden in the fabric. In garter stitch (knit every row), the increase bar is more visible, but it still blends reasonably well because garter stitch is textured.
In ribbed patterns, you may need to decide whether to KFB into a knit stitch or a purl stitch depending on where the increase falls. If the pattern calls for an increase in a knit column, use KFB on a knit stitch. If it falls in a purl column, use KFB on a purl stitch. This keeps the rib pattern aligned.
In lace or colorwork, KFB is less common because the increase bar can disrupt the pattern. Patterns that use lace or colorwork usually specify a different increase method, so always check your pattern instructions before choosing.
When to Use KFB Versus Other Increase Methods
KFB is fast and works well for increases that happen in the same row. It is ideal when you need to add one or two stitches at a time in the middle of your work, such as shaping a neckline or widening a sleeve gradually.
If you need to add many stitches at once (like casting on new stitches for a sleeve cap), casting on is faster than doing multiple KFBs. If you want an increase that is completely invisible, a lifted increase or a yarn-over may be better choices. If your pattern specifies a particular increase method, always follow the pattern—different increases create different visual effects, and the designer chose a specific one for a reason.
Frequently Asked Questions
Does KFB create a hole in the fabric?
No, KFB does not create a hole. It creates a small bar or bump at the base of the increase, but the fabric remains solid. If you see a hole, you may have accidentally dropped a stitch or worked a yarn-over instead.
Can I use KFB to increase multiple stitches in a row?
Yes, you can KFB into every stitch or every other stitch to add multiple stitches in one row. This is common when shaping the crown of a hat or widening a piece quickly. Just remember that each KFB doubles the stitch count in that location, so plan accordingly.
What if I accidentally twisted the back loop?
A twisted stitch will look uneven and lean to one side. On the next row, you can fix it by knitting or purling through the back loop to untwist it. If you do not notice until later, you can also use a crochet hook to fix it in the finished fabric.
Is KFB the same as M1 (make one)?
No, they are different increases. KFB works into an existing stitch and creates a visible bar. M1 lifts the strand between two stitches and is nearly invisible. Patterns will specify which one to use, so check your instructions.
Can I use KFB on the edge of my work?
Yes, KFB works fine on edge stitches. In fact, the increase bar is often less noticeable on edges because it gets hidden in seams during finishing. Many patterns use KFB one or two stitches in from the edge for this reason.