PTBL – How to purl through the back loop

A step by step tutorial to “purl through back loop”. Learn PTBL the easy way

So, your pattern tells you the purl one through the back loop to create a twisted stitch on your needles? But how do you knit it?

In this tutorial, I’m going to show you exactly how to purl through the back loop – step by step.

ⓘ In knitting patterns, this stitch is abbreviated with Ptbl. There is a corresponding Ktbl, knit through back loop, stitch as well.


Purling through the back loop is not much different than the regular purl stitch and creates almost the same stitches in your pattern. They use a bit more yarn and appear a bit twisted. Here’s how you knit Ptbl:

Hold the yarn in front of your work as you would for a normal purl stitch.

Step 1: Insert the needle into the back leg of the first stitch on your left needle from right to left (you could also say from behind).

Insert the needle from the back of the loop to the front

Step 2: Wrap your needle around the working yarn counter-clockwise (just the way like you would normally purl).

catch the yarn from the front to purl through the back loop

Step 3: Purl the working yarn through the loop and slide off the stitch from your left needle.

purl through the back loop pull the yarn through

And that’s it. That’s your purl through the back loop stitch. It’s quite simple.

A twisted purl stitch (through the back loop) on the right needle
A final stitch on your right needle

Make sure to keep a nice tension on your working yarn and use one finger to bring the yarn even further to the front (see picture step 2) so pulling the yarn through is as easy as possible. Then, you can knit those stitches more or less as fast as regular purl stitches with a little practice.

Good to know:

Sometimes your pattern requires you to ‘purl yarn over through back loop’. The technique is absolutely identically. Instead of a purl stitch you have a yarn over on your left needle. Again, you have to find the back loop of that yarn over, insert your needle from right to left, and purl it.

So, what do you need the Ptbl for?

Close up of a twisted rib stitch knitting swatch
A swatch in a twisted rib stitch (*Ktbl,Ptbl*)

If you are knitting a flat piece, your chart sometimes doesn’t show you the return rows and simply states “knit every stitch as they appear” (or something similar). So, if you see a twisted stitch (as a result of a Ktbl in the first row) in the return row, you will have to purl through the back loop so it will appear correctly in your pattern. A twisted rib stitch is a perfect example, but there are others.

Also, if you see a twisted purl stitch on your needles the other way where one shouldn’t be (typically after you picked up stitches after frogging or when you turn the heel of socks, etc), you can knit this twisted purl stitch through the back loop to rectify that mistake.

Purl 2 together through back loop

Sometimes patterns require you to purl two together through the back loop. You’ll knit this exactly the same as above, but in this case, you’ll pick up two stitches from behind instead of just one. First in the second stitch on your left needle, then into the first stitch (sounds like two steps, but it’s one motion). It can be a bit tricky to insert the needle into the second stitch, but you can use the tip of your needle to loosen it up a bit from the front if you really can’t fit in.

So, this was my little knit through back loop tutorial. I hope I was able to show you how to knit this versatile stitch. Make sure to comment with your questions if you have any.

How to knit a purl through back loop stitch

2 thoughts on “PTBL – How to purl through the back loop”

  1. Hello! I love your blog. Is there some way to close the loop on a yarn over when working in the round (i.e., if you are not purling on the wrong side and can’t purl through the back loop)? Thanks!

    • Hey Lena,
      happy to hear that.
      Of course, you can close the gap on the right side as well. Just do a knit through back look (ktbl).
      As a general rule, almost all stitches have a knit and purl equivalent. So there’s k2tog and p2tog. SSK, and SSP, and in almost all cases they are mirror-inverted, and you can use them when knitting in the round. Just the way you produce stockinette stitch by knitting the right side and purling the wrong side (and when you knit it in the round you just knit across).
      Hope that helps.


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