If you can knit the basic stitches, including binding off and making buttonholes, you can knit a sweater for a dog. Yorkie dogs are small and often need an extra layer of warmth during cold weather seasons; knitting a yorkie dog sweater will help your dog stay cosy and warm even on the coldest of days. Knit your sweater in a worsted weight washable yarn and add buttons for an easy-on, easy-off style.
Prepare your measurements. Measure around your dog's chest; this is measurement A. Measure the length from your dog's neck to her front legs; this is measurement B. Measure the length down your dog's back from her neck to her waist; this is measurement C. Write these measurements down for later use.
Knit a gauge swatch. Cast on 20 stitches using worsted weight yarn and size US 6 knitting needles (straight or circular). Knit in the following rib pattern: knit two, purl two. Continue this pattern across the first row, and then when you turn your work be sure to purl the knitted stitches and knit the purled stitches. Knit for 20 rows and do not bind off. Instead, measure how many stitches you made in one horizontal inch and how many rows you made in one vertical inch. Use these numbers to calculate how many stitches you need to cast on to reach a width of measurement A (number of stitches per inch times A inches). Then calculate how many rows you will need to knit before you reach length B (number of rows per inch times B inches) and length C (number of rows per inch times C inches).
Unravel your gauge swatch. Cast on the number of stitches you determined for gauge A. Knit four stitches, then complete your knit two purl two ribbing, and knit the last four stitches. Follow this pattern on every row; always knit the first and last four stitches and then complete your ribbing pattern in the centre of each row. This will add a garter stitch border to the sides of your Yorkie dog sweater.
Starting at row 5 and every fourth row after that, make a buttonhole. To do this, follow your row pattern up to the second garter stitch border. For the last four stitches of these rows, complete the following pattern: Knit one, yarn over, knit two together, knit one. This will create a hole in your stitching that you can use as a buttonhole later. Continue to knit in this manner until you have completed the number of rows to reach gauge length B.
For the next row, you will need to place the leg holes. Measure the distance from the centre of your dog's back to his right front leg; then measure the distance between his right and left front legs. Knit in your pattern the number of inches for your first measurement, then bind off ten stitches. Continue to knit the number of inches for your second measurement, then bind off ten more stitches and finish the row as usual. For the row after this, knit your row and then cast on ten stitches in each place that you bound off ten stitches before. This will create two holes for the dog's front legs to fit into.
Continue to knit your dog sweater until you have completed the number of rows determined in your gauge measurement C. Make sure to add your buttonholes every four rows. Bind off loosely at the end of your last row.
Sew buttons onto the dog sweater to match up with the buttonholes you made. Put the sweater onto your dog by putting her legs through the armholes you made and buttoning the sweater down her back. The ribbed stitch pattern you used will help the sweater stretch around her body.
If you find the sweater is too large, sew a few lengths of elastic cording into the stitches going horizontally across the sweater. This will help tighten it. You can also move the buttons in toward the centre so you can button it more tightly.