The question behind “how to change yarn when crocheting” is usually not about the join itself, it is about timing: how do you know the right moment to change before you run out mid-stitch. I ruined more than one blanket border early on by guessing wrong and ending up two stitches short of a full row. Once you know what to check, you can plan the change instead of reacting to it.
The Three Signals to Watch For
Most yarn changes happen for one of three reasons, and each one gives you a different amount of warning.
Running low is the most common trigger, and it is also the one people misjudge most. A skein that feels light is not a reliable signal on its own, since fiber content changes how heavy the same yardage feels in your hand.
The other two triggers, a planned color change in the pattern or a flaw in the yarn itself, like a knot or a thin spot, usually give you no warning at all. You just hit them mid-row and have to react.
How to Check Before You Run Out
Lay your remaining yarn out flat and fold it in half, then in half again, until you have roughly eight equal lengths. Each fold represents about one eighth of what is left, and you can compare that against how much yarn one row or round typically eats.
For a rough rule I use on worsted weight projects: one row of double crochet across 20 stitches uses about a yard and a half. If my remaining yarn folds out to less than two of those yard-and-a-half lengths, I plan my change for the end of the current row rather than pushing into the next one.
This planning step matters because a change made at a row’s edge is far easier to hide than one forced mid-row by running out unexpectedly.
Making the Change Once You Are Ready
Once you have decided this is the row, the change itself is simple: finish your last stitch of the old yarn with two loops still on the hook, then pull the new yarn through to complete it. That single motion is the entire technique, and it works the same way at any yarn weight.
I keep a full walkthrough of that motion, plus stitch-by-stitch timing for taller stitches like double and treble crochet, on the how to switch yarn when crocheting page if you want the mechanics in more detail than fits here.
What to Do With a Damaged or Knotted Section
If the trigger is a flaw in the yarn rather than running low, cut the yarn a few inches before the bad section instead of crocheting over it. Working around a knot or thin spot inside a stitch almost always leaves a visible bump or a weak point that can snap later.
I treat any manufacturing knot inside a skein the same way I treat running out: as a planned change point, not something to hide mid-stitch.
Frequently asked questions
How do you know when to change yarn in crochet?
Fold your remaining yarn into equal lengths and compare it to how much one row typically uses, roughly a yard and a half per 20 stitches of double crochet in worsted weight. If you have less than two rows worth left, plan your change for the end of the current row. Pattern-directed color changes and yarn flaws like knots are the other two common triggers, and both usually need to be handled the moment you reach them.
Should you crochet over a knot in the yarn?
No. Cut the yarn a few inches before the knot and treat it as a planned yarn change instead of crocheting through it. Knots inside a stitch tend to create a visible bump on the right side of the fabric and can also weaken the yarn at that exact point over time.
Can you change yarn mid-row if you have no choice?
Yes, and the join itself works exactly the same as changing at a row’s edge, but the color or texture shift will be more visible sitting inside the fabric. If you genuinely run out mid-row, make the change and keep going, then plan more carefully on the next skein by checking remaining yardage before you start the row.
Wrap Up
Changing yarn when crocheting is really a timing question first and a technique question second. Once you can estimate remaining yardage, the actual switch is the same simple move every time. For the full step-by-step join, including how it changes for taller stitches, see how to switch yarn when crocheting, or read about invisible color changes if the trigger for your change is a planned stripe or color block.