Before starting to make any garment, you must make a tension sample in order to measure stitch tension. You should do this in order to check your individual control of the yarn against the pattern you are following - so that the desired measurements are the same as in the pattern.
The stitch gauge, or tension, is always given at the beginning of a pattern. It is written as the number of stitches and the number of rows in a particular pattern, e.g. stocking stitch, to a specified size such as 5cm using the yarn and needles called for in the pattern.
An example is 22 sts and 30 rows to 5cm over st st on no.5 needles. A variation in tension within a garment will result in an uneven appearance. By knitting the required number of stitches and rows, your sample will reveal whether the yarn and needles you are using will make up into the size and shape you require.
Adjusting the Stitch Gauge
The ball band provides important information regarding stitch tension. The one shown to the left gives metric and US crochet hook and needle sizes and the ideal tension sample.
If the number of stitches given in the pattern knit up too wide a measure, your knitting is too lease and you change your needles to a smaller size. If they knit up too small a measure, then your knitting is too tight and you should change your knitting needles to a larger size.
Changing needles on size larger or one size smaller make a difference of one stitch usually every 5cm. Changing your needle size will normally be sufficient to adjust the dimensions. Sometimes, however the width will match but not the length.
If there are too many vertical rows to that called for in the pattern, you must calculate the length of the garment from your tension sample and adjust the increasing and decreasing rows accordingly. However in certain patterns such as raglan or set-in sleeves, the shaping is dependent on a specific number of vertical rows. If your vertical tension matches but not your horizontal then in this case it is better to lose some stitches across the width.
Making a tension sample
Using the same yarn, needles and stitch pattern called for in the pattern, knit a sample slightly larger than 5cm square. Smooth out the finished sample on a flat surface larger than 5cm square. Smooth out the finished sample on a flat surface being careful not to stretch it. Using pins, mark out the tension measurement given in the chosen pattern.
Measuring the number of stitches
To determine the width of the knitting, place a steel ruler or tape measure across the sample and count the number of stitches between the pins. Remember to include any half stitches over the width of the garment; a half stitch which is left uncalculated may amount to several inches in the final width.
Measuring the number of rows
To determine the length of the knitting, place a steel ruler or tape measure vertically along the fabric and count the number of rows to the inch.