Formula and example
How it is calculated
yarn weight = finished area / swatch area × swatch weight × (1 + reserve/100)
Worked example
From a 10 × 10 cm, 5 g sample: a 100 × 150 cm blanket requires 750 g; with 10% reserve, 825 g, i.e. 9 balls of 100 g.
Things to check
- Measure a washed, blocked and completely dry swatch made in the same stitch pattern as the finished piece. Make a new swatch if the yarn composition or stitch pattern changes.
- The calculation applies to rectangles. Account for the separate requirements of fringes, edging, seaming, and parts with different patterns in the reserve or a separate calculation.
Frequently asked questions
How does the swatch help?
You measure the combined material requirement of your own yarn, needles, pattern, and tension. Pieces of the same size but different patterns may use different amounts of yarn.
How should I calculate for shaped garments?
The calculator works for rectangles. For a complete pullover, you must also consider the actual area, shaping, ribbing, and assembly of the parts.