The Basic Method: Joining a New Color Mid-Row

To switch colors while knitting, drop the old yarn and pick up the new one at the point where you want the color change to happen. Knit the next stitch with the new yarn, leaving a short tail of the new color (about 4 inches) hanging on the wrong side of your work. The old yarn tail will also be on the wrong side. You now have two tails to weave in later, but your color change is complete—you can keep knitting with the new color when ready.

The key is that you don't tie the yarns together or make a knot. A knot creates a bump that shows on the finished piece and can come undone. Instead, the tension of your next few stitches holds both tails in place while you work. This method works whether you're switching colors in the middle of a row, at the end of a row, or at the beginning of a new row.

Key Takeaways

  • Drop the old yarn and pick up the new yarn at your color change point, leaving 4-inch tails of both colors on the wrong side of your work.
  • Knit the first stitch with the new yarn without tying the yarns together—tension from your stitches will hold the tails in place.
  • Weave in both tails along a row of stitches on the wrong side after you finish knitting, using a tapestry needle.
  • Stranding (carrying yarn across the back) works for small color blocks; cutting and rejoining works for larger sections or when colors are far apart.
  • Practice your color changes on a swatch before starting a project so the transition looks even and the tension stays consistent.

Stranding: Carrying Yarn Across the Back

If your color blocks are small—say, 5 stitches or fewer—you can carry the unused yarn across the back of your work instead of cutting it. This is called stranding. When you switch back to the first color a few stitches later, the yarn is already waiting for you on the wrong side.

To strand, drop the active yarn and pick up the waiting yarn. The yarn you just dropped now floats across the back of your stitches until you need it again. Keep these floats loose enough that they don't pucker your fabric—they should have about the same amount of slack as the stitches themselves. If the floats are too tight, your knitting will bunch up; if they're too loose, they'll snag when you wear the piece.

Stranding works well for colorwork patterns like Fair Isle or straightforward geometric designs where colors alternate frequently. It's faster than cutting and rejoining because you don't have tails to weave in. However, long floats (more than 5 stitches) are a problem: they catch on fingers or jewelry when you wear the garment. For larger color blocks, cut the yarn instead.

Cutting and Weaving In Tails

When you have a large block of one color followed by a large block of another, cut the yarn rather than strand it. Cut the old color about 6 inches from your work, then pick up the new color and knit with it, leaving a 4-inch tail of the new yarn on the wrong side. You now have two separate tails to deal with, but no long floats on the back.

After you finish knitting, thread a tapestry needle (a blunt needle with a large eye) with one tail. On the wrong side of your work, weave the tail through the bumps of a row of stitches for about 2 inches, then trim the excess. The woven-in tail becomes part of the fabric and won't unravel. Repeat with the second tail. This takes a few minutes per color change, but it's the only safe method for large color blocks.

Avoiding Common Mistakes at Color Changes

The most common mistake is pulling the new yarn too tight on the first stitch. This creates a loose loop of old yarn on the wrong side and a tight, distorted stitch where the colors meet. Instead, knit the first stitch with the new yarn at normal tension—not loose, not tight. The tails will settle into place as you work the next few stitches.

A second mistake is tying the old and new yarns together. A knot is visible from the right side, especially in light colors, and it can slip or come undone over time. Never knot. A third mistake is stranding a float that's too long. If you're carrying yarn across more than 5 stitches, cut it instead—the float will snag otherwise.

Finally, some knitters weave in tails while the piece is still on the needles. Wait until you've bound off and removed the work from the needles. Weaving in while stitches are live can accidentally drop a stitch, and you won't notice until later.

Color Changes at the End of a Row

Switching colors at the end of a row is the easiest place to do it because you're already stopping to turn your work around. Knit to the last stitch of the row with the old color, then drop the old yarn. Pick up the new yarn and purl the first stitch of the next row (or knit it, depending on your pattern). Leave 4-inch tails of both colors hanging on the wrong side.

The advantage of changing colors at a row edge is that the color change line is straight and clean. There's no risk of a distorted stitch in the middle of a row. If your pattern allows it, plan color changes for the end of rows whenever possible. This is especially helpful when you're learning, because the technique is simpler and the results are more forgiving.

Practicing Color Changes on a Swatch

Before you start a colorwork project, knit a small swatch—about 20 stitches wide and 30 rows tall—and practice switching colors at different points. Change colors in the middle of a row, at the end of a row, and try both stranding and cutting. Pay attention to how tight or loose your tension becomes at each color change.

Most knitters find that their tension changes slightly when they switch yarns, especially if the new yarn is a different weight or texture. A practice swatch shows you this before you're committed to a full project. You can also test how your tails look when woven in, and whether your stranded floats are the right length. Keep the swatch—it's a reference for future projects using the same yarn.

Frequently Asked Questions

Should I tie the two yarns together when I switch colors?

No. A knot creates a visible bump on the right side of your work and can slip or come undone. Instead, drop the old yarn and pick up the new yarn, leaving tails on the wrong side. The tension of your stitches will hold both tails in place.

How do I keep my tension even when switching colors?

Knit the first stitch with the new yarn at your normal tension—not tight, not loose. The tails will settle as you work the next few stitches. If the first stitch looks distorted, your tension was too tight. Practice on a swatch until the transition feels smooth.

Can I strand yarn across the entire back of a sweater?

No. Long floats (more than 5 stitches) will snag on fingers or jewelry when you wear the piece. For large color blocks, cut the yarn and weave in the tails instead. Stranding works only for small color changes that happen frequently.

What if I run out of yarn in the middle of a row?

Treat it like a color change: drop the old yarn, pick up a new ball of the same color, and knit the next stitch with the new yarn. Leave 4-inch tails on the wrong side and weave them in later. This method works whether you're switching colors or continuing with the same color.

Do I have to weave in tails right after I finish knitting?

No. You can weave in tails anytime after you've bound off and removed the work from the needles. Many knitters save tail-weaving for the end because it's easier to do all of them at once. Just make sure the tails are woven in before you wear or wash the piece.