What Knit Front and Back Does

Knit front and back (often written as KFB) is a way to increase one stitch by working into the same loop twice before dropping it off the needle. You knit through the front of the stitch as normal, leave it on the left needle, then knit through the back of that same stitch, and only then slip it off. This creates two stitches where there was one, and it's one of the most common increase methods in patterns.

The increase sits slightly to the left on your fabric because the new stitch comes from the base of the original stitch. This matters if your pattern calls for it specifically—some patterns choose KFB for its appearance, while others use different increases to avoid a visible slant. When you see KFB in a pattern, it means the designer wants this particular look or placement.

Key Takeaways

  • Knit front and back means working twice into the same stitch before dropping it off the needle, creating two stitches from one.
  • The new stitch appears slightly to the left of the original, which creates a visible increase line that some patterns use intentionally.
  • You must keep the stitch on your left needle after the first knit, then knit into the back loop before slipping it off.
  • The increase works the same way on knit rows and purl rows—purl front and back (PFB) follows the identical principle.

The Step-by-Step Motion

Insert your right needle through the front of the stitch on your left needle, from left to right, the way you would for a normal knit stitch. Wrap the yarn around your right needle and pull the loop through, but do not slip the stitch off the left needle yet. You now have one new stitch on your right needle and the original stitch still sitting on your left needle.

Without moving the stitch, insert your right needle through the back of that same stitch on the left needle. The needle goes in from right to left this time, entering through the back loop. Wrap the yarn around your right needle again and pull through. Now slip the original stitch off the left needle. You have completed one KFB increase and added one stitch to your row.

The whole motion takes about three seconds once you have done it a few times. The key is remembering not to drop the stitch after the first knit—that is the mistake that stops most people. Some knitters find it helpful to say "knit, don't drop, knit the back, drop" as a rhythm.

Where Knit Front and Back Appears in Patterns

KFB shows up most often in shaping sections—increases for sleeve caps, raglan armholes, or the crown of a hat. Because the increase leans slightly left, patterns sometimes use it on both sides of a center stitch to create a balanced increase pair, or they use it only on one side where a slant is wanted. A pattern might say "KFB, knit to last stitch, KFB" to increase one stitch on each end of the row.

You will also see it in lace patterns and colorwork, where the placement of the new stitch matters for the design. Some patterns use KFB instead of other increases straightforward because the designer prefers how it looks. If a pattern does not specify which increase to use, you can usually substitute KFB for other single-stitch increases like M1 (make one) or lifted increases, though the fabric will look slightly different.

Common Mistakes and How to Avoid Them

The most common error is dropping the stitch off the left needle after the first knit. You will end up with only one stitch instead of two, and your increase will not happen. Slow down on the first few KFBs in a row and look at the stitch—it should still be sitting on the left needle after you pull the first loop through. If you are not sure whether you dropped it, you have probably dropped it.

The second mistake is knitting into the front loop twice instead of the front and then the back. This creates a twisted stitch on the second loop, which will look uneven. The back loop is the one farther away from you—you have to reach around the stitch to enter it from the back side. It feels awkward at first, but the angle becomes natural with practice.

Tension can also be loose around a KFB increase because you are working twice into the same stitch. The new stitch may look bigger than the others. Tighten slightly as you pull the second loop through, and the stitch will even out as you work the next row.

Knit Front and Back on Purl Rows

If your pattern calls for an increase on a purl row, you use the same principle but with purl stitches. Purl front and back (PFB) means purling through the front of the stitch, leaving it on the needle, then purling through the back loop before dropping it off. The motion is identical to KFB except you are purling instead of knitting.

The increase leans the same direction whether you use KFB or PFB, so a pattern that says "increase 1" on a purl row usually means PFB if the pattern is consistent. Some patterns will specify KFB on a purl row if they want the stitch to look a certain way on the reverse side, so always check the pattern notes.

How Knit Front and Back Compares to Other Increases

KFB is faster than make-one increases (M1) because you do not have to pick up a strand between stitches. It is also more visible, which is why some patterns avoid it in places where they want the increase to blend in. Make-one increases are nearly invisible, while KFB creates a small bump or line that becomes part of the design.

Lifted increases (picking up the stitch below and knitting it) are also common, and they lean in the opposite direction from KFB. If a pattern calls for balanced increases on both sides of a center stitch, it might use KFB on one side and a lifted increase on the other to create a symmetrical look. For most projects, you can swap KFB for other single-stitch increases without major problems, though the appearance will shift slightly.

Frequently Asked Questions

Does knit front and back create a hole in the fabric?

No. KFB creates a small bump or line where the increase sits, but not a hole. If your pattern has holes, those come from yarn overs, which are a different technique. A KFB increase is a solid stitch that adds width to the fabric.

Can I use knit front and back on every stitch in a row?

Yes, though it will double your stitch count and create a very textured, bumpy row. This is sometimes done intentionally for decorative increases, but most patterns use KFB only in specific places. If you knit front and back across an entire row, you will have twice as many stitches as you started with.

What if I accidentally knit front and back when the pattern didn't call for it?

You will have one extra stitch in that spot. If you catch it on the same row, you can drop back and fix it. If you do not notice until later, you can either frog (rip out) back to that row or continue and decrease elsewhere to balance it out. Most knitters just keep going—one extra stitch rarely ruins a project.

Is the bump from knit front and back supposed to show on the finished garment?

Usually yes, especially in shaping areas like sleeve increases. The bump is part of the design. If you want increases to be invisible, use make-one increases instead. Some patterns use KFB intentionally because the visible increase line is part of the pattern's look.