Start with yarn weight and needle size that match

A blanket knitted on straight needles works best when you choose yarn and needles that are already paired together. Look at the yarn label — it will say something like "worsted weight" or "bulky weight" and recommend a needle size, usually written as a number (like US 8) or a millimeter measurement (like 5mm). Buy needles in that size. Straight needles come in pairs, and for a blanket you want needles that are at least 10 inches long so you can hold stitches comfortably as your blanket grows.

Blankets are forgiving projects because small mistakes disappear into the fabric. Worsted weight yarn and US 8 to US 10 needles are a safe starting point if you have never made a blanket before — the stitches are large enough to see clearly, and the work moves quickly. Avoid thin yarn (called fingering or sport weight) for your first blanket; it takes much longer and requires more precision.

Key Takeaways

  • Cast on 100 to 150 stitches depending on how wide you want your blanket, using the long-tail cast-on method or another method you already know.
  • Knit every row in garter stitch (knit stitch on both the front and back of every row) to create a soft, squishy fabric that does not curl at the edges.
  • Count your rows every 10 rows so you know when your blanket is long enough — most blankets are roughly square or slightly longer than they are wide.
  • Bind off all stitches when you reach your target length, then weave in the yarn ends with a needle to finish the blanket.
  • A typical blanket takes 40 to 80 hours of knitting depending on yarn weight and size, so plan for a project that spans several weeks.

Cast on the right number of stitches for your blanket width

The number of stitches you cast on determines how wide your finished blanket will be. A small lap blanket is usually 40 to 50 inches wide, and a larger throw is 50 to 60 inches wide. To figure out how many stitches to cast on, knit a small test swatch first: cast on 20 stitches, knit 20 rows in garter stitch (knit every row), then bind off and measure how wide it is. Divide your target width in inches by the width of your swatch, then multiply by 20 to get the number of stitches you need.

For example, if your swatch is 4 inches wide and you want a 48-inch blanket, you would cast on (48 ÷ 4) × 20 = 240 stitches. This math takes 15 minutes but saves you from casting on the wrong number and having to start over. Use the long-tail cast-on method if you know it, because it creates a neat edge that looks finished. If you know a different cast-on method, use that instead — the specific method matters less than casting on loosely so your edge stitches are not tight.

Knit in garter stitch until your blanket reaches the length you want

Garter stitch is the simplest blanket stitch: knit every stitch on every row, without any purling. This creates a bumpy, textured fabric that looks the same on both sides and does not curl at the edges — important for a blanket that will be washed and draped over furniture. Sit in a comfortable chair, hold one needle in each hand, and knit one row at a time. After you finish a row, turn your work around and knit the next row the same way.

Blankets take time. A typical throw blanket in worsted weight yarn takes 40 to 80 hours of knitting. Set a realistic pace — knitting for 30 minutes to an hour most days means you will finish in 6 to 12 weeks. Count your rows every 10 rows by placing a stitch marker or a piece of yarn in your work so you can track your progress. Most blankets are roughly square or slightly longer than they are wide, so if your blanket is 48 inches wide, aim for 54 to 60 inches long. Divide your target length by the row gauge from your swatch to know when to stop.

Watch for common mistakes that affect the finished blanket

The most common mistake is casting on too tightly, which makes the cast-on edge stiff and hard to work with. Cast on loosely, even if it feels awkward. If your cast-on edge is already tight, you can pick it up later and re-cast it with a looser tension — it is worth fixing before you knit 50 rows.

The second mistake is accidentally increasing or decreasing stitches. This happens when you knit into the loop between stitches by accident (creating a new stitch) or drop a stitch without noticing. Count your stitches every 10 rows. If you have more stitches than you started with, you are accidentally increasing; if you have fewer, you dropped one. A dropped stitch in garter stitch is straightforward to fix: use a crochet hook to pull the dropped stitch back up through the rows above it, working from bottom to top.

The third mistake is knitting too tightly overall, which makes your blanket stiff instead of soft. If your blanket feels hard and dense, you are probably tensioning the yarn too tightly as you knit. Relax your grip slightly and let the yarn flow more freely through your fingers. A blanket should feel squishy and drape easily.

Bind off and finish the edges

When your blanket reaches your target length, bind off all stitches to find them so they do not unravel. The standard bind-off is straightforward: knit two stitches, pass the first stitch over the second stitch and off the needle, then knit one more stitch and repeat until all stitches are bound off. Work loosely so your bind-off edge is not tight. Cut the yarn, leaving a 6-inch tail, and pull it through the last stitch to find it.

Weave in the yarn ends with a yarn needle (a large, blunt needle with an eye big enough for yarn). Thread the tail through the needle, then weave it through the bumps of garter stitch for about 2 inches, going back and forth to anchor it. Trim the excess yarn close to the fabric. Do this for both the cast-on tail and the bind-off tail. Wash your blanket in cool water with mild detergent, then lay it flat to dry or tumble-dry on low heat depending on the yarn fiber content — check the label.

Adjust your blanket size by changing yarn weight or stitch count

If you want a larger blanket, cast on more stitches or use thicker yarn. Bulky weight yarn knits much faster than worsted weight, so a bulky blanket can be finished in 3 to 4 weeks instead of 8 to 12. The trade-off is that bulky yarn is more expensive per blanket and creates a heavier finished blanket. If you want a smaller blanket, cast on fewer stitches or use thinner yarn, but remember that thin yarn takes much longer to knit.

You can also make a rectangular blanket instead of a square one by casting on fewer stitches and knitting more rows, or casting on more stitches and knitting fewer rows. A baby blanket is typically 30 to 40 inches square, a lap blanket is 40 to 50 inches square, and a throw is 50 to 60 inches. Measure a blanket you already own to decide what size feels right for your space.

Frequently Asked Questions

How much yarn do I need for a blanket?

A typical throw blanket in worsted weight yarn uses 2,000 to 3,000 yards of yarn. A lap blanket uses 1,500 to 2,000 yards. Check the yardage on the yarn label and buy enough to reach your target yardage, then add one extra skein in case you need it. It is better to have leftover yarn than to run short near the end.

Can I use circular needles instead of straight needles?

Yes, circular needles work for blankets and many knitters prefer them because they distribute the weight of the blanket more evenly. However, the instructions you asked for are specifically for straight needles, so if you want to use circular needles, you would follow the same stitch pattern but hold the needles differently. Straight needles are fine for blankets up to about 50 inches wide.

What do I do if I drop a stitch?

In garter stitch, a dropped stitch is visible as a horizontal loop. Use a crochet hook to pick it up: insert the hook through the dropped stitch from front to back, catch the horizontal loop above it, and pull it through. Repeat for each row above the dropped stitch until the stitch is back on the needle, then continue knitting.

How do I know if my blanket is big enough?

Measure your blanket with a tape measure as you knit. Most blankets are roughly square or slightly longer than they are wide. If you cast on for a 48-inch width, aim for 54 to 60 inches long. Lay your blanket on a bed or couch to see how it looks before you bind off — you can always knit more rows if it feels too small.

Should I block my blanket after I finish knitting it?

Blocking (wetting and pinning your blanket to shape) is optional for garter stitch blankets because garter stitch is naturally flat and does not curl. Washing your blanket in cool water and laying it flat to dry is usually enough. If your blanket has uneven edges or looks wavy, you can block it by pinning it to a blocking board while damp, but most knitters skip this step for blankets.