How to knit the Central double increase

A step by step tutorial on the central double increase (CDI) and how to improve it so the holes are less visible

Does your knitting pattern ask for a centered double increase? But you have no idea how to knit it? Well then, in this tutorial, I’m going to show yous step by step how to do a centered double increase you can use in the middle of shawls or advanced lace patterns.

And the best part: I am not only going to show you one way to do it, but also a couple of very helpful variations so you can make the holes smaller (for more variations, also check my ultimate list of knitting increases)

A swatch with the stanard central double increase

ⓘ In knitting patterns, you’ll often find the abbreviations CDI for Centered Double Increase. Sometimes it also says INCTO3 (increase to 3 stitches). This usually does not refer to a specific technique, but rather just a double increase that is centered (as opposed to leaning to the left or the right).

So, let’s dive right into it.

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How to knit the central double increase

close up of a knitting swatch with the central double increase

The most common and popular way to do a central double increase is by knitting a KBF and combining it with a variation of the classic M1.

Active Time 1 minute
Total Time 1 minute

Instructions

  1. Knit into the back loop of the stitch you want to be in the center. But don't drop the stitch as normal. Keep it on your needles.
    Start by knitting into the back loop of a stitch to start the central double increase
  2. Knit into the front loop of the same stitch, and keep it on the needle.

    Knit the front loop of the same stitch
  3. Identify the little strand between the two stitches you just created and lift it onto your left needle (using the left needle from back to front).

    lift the strand between two stitches with your left needle
  4. Knit that extra loop through the back loop.

    Knit the lifted stitch through the back loop to finish the central double increase
    As I said, it boils down to a combination of a KBF and a lifted increase

    the final central double increase on the right needle

CENTERED DOUBLE INCREASE VARIATION #1

swatch of the central double increase altenative with no holes

For a neater version of the standard double increase with smaller holes, you should start with a KFB (Knit front back) instead of a KBF (Knit Back front) and then just knit the lifted increase.

Step 1: Knit into the front loop.

start by knitting into the front loop

Step 2: Knit into the back loop.

then knit into the back loop like a normal kfb

Step 3: Pick up the loop between those two stitches from behind again (will be a bit harder to find).

lift the strand between two stitches for the alternative double increase

Step 4: Knit it through the front loop.

knit the lifted stitch through front loop

This version is a bit harder to work, mainly because knitting a lifted loop through the back loop requires a sharp-pointed needle. But I think it is worth it.

Central double increase Variation #2

A symetrical alternative of the centered double increase knitting

For a different look and feel, you can also combine two backward loop increases around one central knit stitch. It’s actually the easier way to knit it, but it runs of creating a sort of laddering effect. On the plus side, it doesn’t shorten any strands between stitches, so it doesn’t pucker the fabric and looks very symmetrical.

Step 1: Knit up to the stitch that will be the center of your increase.

Step 2: Wrap the working yarn around your thumb counter-clockwise.

create a backwardloop increase to the right as a start

Step 3: And pick up the loop you created with the right needle from above/behind and pull tight.

A rightleaning backward loop increase on the right needle

Step 4: Knit one stitch (this one is going to be the center of the increase).

knitting one knit stitch as normal

Step 5: Wrap the working yarn around your thumb clockwise.

create a backwardloop increase after that knit stitch

Step 6: Pick up the loop you created from below and pull tight.

the final alternative backwardloop double increase

Note: If you want to close the somewhat loose loops of this central double increase variation, then you’d have to purl the two stitches to the left and the right through the back loop. This, however, will create visibly twisted stitches, so you have to decide between two evils, sort of.

Centered Double Increase Variation #3

centered double increase knit with a combination of a kll and krl

If you would like a denser fabric with less holes, then you’ll have to knit a KLL and KRL into the same stitch. This will shorten the stitches quite a bit. So, actually I am not sure if it’s the best double increase to use every second row. If your pattern requires double increases every 4 or more rows, then this probably would be my favorite version.

Step 1: Knit up to the stitch you want as the center of your double increase and knit a KRL (Knit Right Loop)

Start by knitting a KRL (Knit right loop) into the left loop

Step 2: Knit the next stitch.

Knit one stitch for this alternative central double increase

Step 3: Knit a KLL (Knit Left Loop).

Knit a KLL (knit left loop) into the same stitch to finish this alternative central double increase

I personally rather like the look of this increase, though it would not be my favorite for the middle of a shawl as, as I said, it does shorten those stitches quite a bit in the middle.

M2 Left and Right

a swatch with the make two left and right increase

A very fun variation of the centered double increase is based on the classic Make Two (M2). While this alternative does indeed create quite big holes, that doesn’t mean it’s less beautiful. It depends on the context. For some lace patterns, this could actually be a neater option. I would like to point out, however, that this is, strictly speaking, no central double increase because you need two stitches, while the classic version works with one stitch.

Step 1: Pick up the strands between two stitches.

lifting the strand between two stitches from the front

Step 2: Now knit a regular M1L by knitting that loop through the backloop, but don’t knit the next stitch yet.

knitting the extra loop through the back loop

Step 2: Instead, pick up the same strand one more time, and now knit the strand through the front loop instead!

lifting the same strand again but this time from the back

This creates a very centered double increase with a beautiful eyelet and very harmonic stitches to either side.

Comparing the 5 alternatives to knit a Central double increase

different central double increase alternatives next to each other
From left to right the five alternatives side by side: KBF, KFB, backward loop increase, KLL/KRL, and M1L/M1R

To finish this already quite a long blog post, I thought it would be nice to compare all these alternatives side by side. As always, I don’t think there is an absolute best and worst technique knitting. Depending on the circumstances and you may want to use one or the other.

I personally like the backward loop variation a lot – especially as it does not shorten the fabric at all. Knitting a central double increase with a KLL/KRL also has it’s charm while I believe that using a M1L and M1R into the strand between two stitches creates the most stunning pattern. Still, this article is meant to present you with options, and you are free to pick your favorite!

So, That’s how you knit the Central double increase. feel free to ask your question in the comments below.

How to knit the central double increase step by step

4 thoughts on “How to knit the Central double increase”

  1. Hello Norman! Thank you for the wonderful instructions! Would this double increase or its variations work if you used garter stitch instead of stockinette? The pattern for a shawl I want to make calls for Yarnover, Knit 1, Yarnover up the central spine to increase by two stitches, but I don’t want to end up with the eyelet holes that yarnovers create. These look like excellent substitutes, but the shawl is in garter stitch rather than stockinette, so I wasn’t sure it would work.

    Reply
    • Hey Mona,

      That’S impossible for me to tell. I’d frankly just knit a little swatch and see if you like it.

      The only problem you should be aware is that some of the versions here won’t work that way. Meaning, you can’t knit a regular KLL when you are knitting garter stitch. But the version where you knit a KFB into the strand between two yarns could look pretty.

      Reply
  2. Hi Norman, Thank you for this thorough tutorial! The centered double increase is new to me, and it’s just what I need for a triangle shawl I’m working from the point up. Your video is clear and your demonstrations are very easy to follow. Also, your blog is well-organized and attractive, a pleasure to visit. I will certainly be back and will recommend your site to others. Many thanks again.

    Reply

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