A tank top is a sleeveless garment you knit in pieces, then seam together

A knitted tank top consists of a front panel, a back panel, and two armhole bands. You knit the front and back as flat rectangles on straight needles, then pick up stitches around the armholes to knit the bands in the round. The whole project takes between 20 and 40 hours depending on yarn weight and your speed. Most tank tops use worsted or DK weight yarn and needles sized between US 6 and US 9.

The process breaks into five stages: choosing your pattern and yarn, casting on and knitting the back, knitting the front (which often has shaping at the neckline), knitting the armhole bands, and seaming the sides together. You do not need advanced skills — if you can cast on, knit, purl, and bind off, you can make a tank top. The main new technique is picking up stitches, which takes practice but becomes automatic after the first armhole band.

Key Takeaways

  • Tank tops are knit in two flat pieces (front and back), then the armhole bands are knit in the round by picking up stitches around the edges.
  • You need a pattern that specifies your size, stitch counts, and row counts for the front and back panels — do not guess at dimensions.
  • The front and back are identical except the front usually has a deeper neckline, which means binding off more stitches at the center.
  • Picking up stitches for the armhole bands is the most unfamiliar step; practice on scrap yarn first if you have not done it before.
  • Seaming the side seams with mattress stitch creates a flat, invisible join that looks professional.

Choosing a pattern and measuring for your size

Start with a pattern written for tank tops, not one adapted from a t-shirt or sweater. Ravelry.com has thousands of free tank top patterns; search by yarn weight, neckline style (crew, V-neck, scoop), and difficulty. Read the pattern all the way through before you buy yarn — patterns vary wildly in how they shape the neckline and armholes, and some require techniques like short rows or increases that others do not.

Measure a tank top you already own that fits you well. Lay it flat on a table and measure the width across the chest (armpit to armpit) and the length from the shoulder to the hem. Compare these numbers to the finished measurements listed in your pattern. Most patterns give finished measurements for sizes XS through XL; pick the size where the chest width is 2 to 4 inches larger than your actual chest (this is called positive ease and prevents the tank from clinging). If you are between sizes, choose the larger one — you can always take in the side seams later.

Casting on and knitting the back panel

Your pattern will tell you how many stitches to cast on. Use the long-tail cast-on, which creates an elastic edge that stretches with the fabric. Cast on the number of stitches for your size, then knit in stockinette stitch (knit on the right side, purl on the wrong side) until the back reaches the length specified in the pattern — usually 15 to 20 inches depending on your height and the style.

When the back is the right length, bind off all stitches using the standard bind-off (knit two stitches, pass the first over the second, repeat). Bind off loosely so the edge does not pucker. Cut the yarn, leaving a 6-inch tail, and pull it through the last stitch to find it. Do not weave in the ends yet — you will do that after seaming.

Knitting the front panel with neckline shaping

The front is knit the same way as the back until you reach the point where the neckline begins. This is usually 4 to 6 inches below the bind-off edge. At this point, your pattern will tell you to bind off a group of stitches at the center (for example, "bind off 20 stitches") to create the neckline opening. You then work each side of the neckline separately, binding off a few more stitches every few rows to slope the shoulders.

Work the left side first: knit to the center, bind off the number of stitches your pattern specifies, then knit to the end of the row. On the next row, purl to the neckline edge, bind off the number of stitches your pattern says (usually 2 to 4), then purl to the end. Repeat this bind-off every other row until you reach the top. The right side is worked the same way but in reverse — you bind off at the neckline edge on the knit rows instead of the purl rows. When both sides are complete, bind off the remaining stitches on each side.

Picking up stitches and knitting the armhole bands

Armhole bands are knit in the round using circular needles or double-pointed needles. To start, you pick up stitches around the armhole opening. Lay the front and back panels flat and count the number of stitches your pattern specifies for the armhole band — usually 60 to 80 stitches depending on the armhole depth. Divide this number by the number of rows around the armhole to figure out how many stitches to pick up per row (usually one stitch every other row).

Using a circular needle one size smaller than your main needles, insert the needle from front to back under the loop at the edge of a row, wrap the yarn around the needle, and pull it through to create a new stitch. Move one row down and repeat. Work your way around the entire armhole. When you have picked up all the stitches, join them into a round by knitting the first stitch with the working yarn. Knit in the round for 1 to 1.5 inches (or the depth your pattern specifies), then bind off all stitches. Repeat for the second armhole.

Seaming the side seams with mattress stitch

Lay the front and back panels on a flat surface with the right sides facing up. Thread a tapestry needle with yarn that matches your tank top. Starting at the bottom corner, insert the needle under the horizontal bar between the first and second stitch on the edge of the front panel. Pull the yarn through, then insert the needle under the same bar on the back panel and pull through. Move up one row and repeat, going back and forth between front and back panels.

Mattress stitch creates a seam that is nearly invisible because you are sewing between the stitches rather than through them. Pull the yarn snug every few inches so the seam does not gap, but not so tight that it puckers. Seam both side seams from the bottom to the armhole. When you reach the armhole, the seam is complete — the armhole band covers the top edge.

Finishing: weaving in ends and blocking

Thread a tapestry needle with each loose yarn tail and weave it through the stitches on the wrong side of the fabric for about 2 inches, then trim the excess. This anchors the tail so it does not unravel. Weave in all tails from casting on, binding off, and color changes.

Blocking shapes the tank top and evens out uneven stitches. Fill a sink with lukewarm water and add a small amount of wool wash (or regular shampoo). Submerge the tank top and let it soak for 15 minutes, then gently squeeze out the water without wringing. Lay it flat on a clean towel, smooth it into shape, and let it dry completely — usually 24 hours. This step is optional but makes a noticeable difference in how polished the finished tank looks.

Frequently Asked Questions

What yarn weight should I use for a tank top?

Worsted weight (medium #4) and DK weight (light #3) are the most common choices. Worsted weight works faster and creates a thicker, warmer fabric. DK weight takes longer but drapes more smoothly and is better for summer. Always follow the yarn weight specified in your pattern — using a different weight will change the finished size.

Can I knit a tank top in the round instead of in pieces?

Yes, but it requires a different pattern and more advanced techniques like short rows for shaping. Patterns written for top-down or bottom-up construction in the round are available on Ravelry, but they are usually marked as intermediate or advanced. Start with a pattern that uses flat pieces if this is your first tank top.

What do I do if my armhole is too loose or too tight?

If the armhole gaps, you picked up too few stitches or your gauge is off. If it is too tight, you picked up too many stitches. You can adjust by picking up one or two more or fewer stitches on the second armhole. If the first armhole is already complete, you can carefully cut and remove the band and re-pick the stitches.

How do I adjust the length if I am taller or shorter than the pattern assumes?

Knit the back and front panels longer or shorter before you begin the neckline shaping. Add or subtract rows from the body length, not from the neckline shaping section. Most patterns tell you the length at which to start shaping — measure from your cast-on edge to that point, then adjust up or down by the number of inches you need.

What is gauge and why does it matter for a tank top?

Gauge is the number of stitches and rows per inch in your knitting. Your pattern specifies a gauge (for example, 18 stitches over 4 inches on US 7 needles). If your gauge is different, your finished tank will be the wrong size. Knit a 4-inch swatch, measure it, and adjust your needle size up or down until your gauge matches the pattern.