Yarn Calculator
How many yards and skeins of yarn a blanket, scarf or other project needs, worked out from a swatch in the same stitch.
How this is calculated
A swatch in your yarn, hook or needles and stitch pattern tells you how much yarn one square inch takes. Unravel it (or measure the yarn before and after) to find the yards used, and divide by the swatch area. The project needs that many yards for every square inch of its area.
The extra percentage covers yarn tails, joining skeins, weaving in ends and small borders; 10 percent is a cautious allowance. The skeins are the total yards divided by the yards on one skein's label, rounded up. Buy them from one dye lot.
If you weighed the swatch instead, the same sums work in grams: enter grams in place of yards for both the swatch and the skein.
Limits
A flat rectangular project in one stitch. Fringe, tassels, big borders, colorwork and textured stitches such as cables or bobbles use more yarn than a plain swatch suggests. A swatch smaller than 4 by 4 inches gives a rougher estimate.