If you want to knit a garment, but you don't think you have the patience to complete an entire sweater, try knitting a tank top. Sweater vests take less time to knit than full sweaters, since they have no sleeves and often hit higher at the waist. Unlike sweaters, which might provide too much coverage for transitional weather in the fall and spring, sweater vests give just enough warmth and are ideal for layering. If you know how to knit and purl and increase and decrease, you'll have no trouble knitting a basic tank top.
Measure the person for whom the garment is intended. You need to know bust circumference, length from underarm to the point where the finished vest will hit at the waist, and shoulder depth. Record your measurements to uses as a guide while knitting the tank top.
Knit a 6-by-6-inch square swatch with the needles and yarn you intend to use. If you want to use a special stitch pattern over the majority of the garment, knit the swatch in pattern.
Wash and block the swatch, and then measure to see how many stitches and rows fit across 4 inches.
Cast on the number of stitches you need to equal bust circumference plus the amount of ease you want the garment to have (0 to 1 extra inch makes a fitted garment, while adding 4 extra inches results in a loosefitting garment). Cast on with a set of circular needles one size smaller than the size you intend to use for the body of the tank top.
Slide a stitch marker onto the end of the right-hand needle and join for working in the round. Position all the cast-on stitches so the ridges sit along the bottom of your needles and be careful not to twist them out of position as you knit the first row.
Knit the first 2 inches of the tank top in knit two, purl two ribbing. The ribbing will keep the edge of your tank top from curling.
Switch to the larger needles and knit in stockinet stitch until the length of your knitting equals the waist-to-underarm measurement minus 2 inches. Depending on where you want the bottom of the tank top to sit, and the length of the wearer's torso, this length will likely fall between 14 and 18 inches.
Knit the front and back of the tank top bodice separately. Divide the stitches on your circular needle in half and place one half on waste yarn.
Knit the front of the sweater back and forth, knitting the front side of the fabric and purling the back side. Continue in pattern for 2 inches, ending with a purl row.
Bind off for the neck in the next knit row. Knit to the centre six stitches, bind them off, and knit the remaining stitches.
Work the stitches on either side of the bound-off stitches separately. On each side of the centre stitches, bind off two stitches every other row, making your bind-offs along the neck edge.
Continue working in the established pattern until either shoulder strap measures 2 1/2 inches wide. Knit straight until the length of your knitting from the first bind-off row equals the wearer's shoulder depth.
Bind off the remaining stitches and begin work on the back.
Knit the back of the tank top straight, knitting across the front of the fabric and purling across the back, until it measures 1 inch shorter than the length of the tank top front (from the point where you split the front and back), ending with a purl row.
Count how many stitches you bound off when you completed each front shoulder strap. This will be the number of stitches you knit at either end of the next row to create the back shoulder straps.
Knit the stitches necessary for the first back shoulder strap and bind off subsequent stitches until only enough stitches to knit the second back shoulder strap remain. Knit the remaining stitches, then knit either shoulder strap separately until they measure 1 inch long and bind off.
Sew the tank top's shoulder straps together, using a yarn needle threaded with the same yarn you used to knit the vest.
Pick up stitches around the neck opening, using the smaller circular needles, work in knit two, purl two ribbing for 1 inch and bind off.
Pick up stitches around each armhole, using the smaller circular needles, work in knit two, purl two ribbing for 1 inch and bind off.
Weave in any loose yarn ends and wash and block your completed tank top.