Crafts calculator
Estimate project yarn from a measured swatch or known area usage, and convert metres and yards.
A 150 × 100 cm blanket is 15,000 cm² (1.5 m²). If a 10 × 10 cm swatch weighs 5 g, the blanket needs 15,000 ÷ 100 × 5 = 750 g, or 825 g with a 10% allowance: 9 skeins of 100 g.
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Every calculation option
Use a finished, washed swatch made in the same yarn and stitch pattern.
Use a measured or pattern-supplied weight per square metre.
Convert a label or pattern length without changing yarn weight.
A 150 × 100 cm blanket is 15,000 cm² (1.5 m²). If a 10 × 10 cm swatch weighs 5 g, the blanket needs 15,000 ÷ 100 × 5 = 750 g, or 825 g with a 10% allowance: 9 skeins of 100 g.
| Input | Value |
|---|---|
| Project length | 150 cm |
| Project width | 100 cm |
| Swatch length | 10 cm |
| Swatch width | 10 cm |
| Swatch weight | 5 g |
| Extra allowance | 10 % |
| Pack size | 100 g |
| Result | Value |
|---|---|
| Project area | 1.5 m² |
| Required quantity | 825 g |
| Packs to buy | 9 |
| Purchase quantity | 900 g |
| Left over | 75 g |
A swatch reflects your yarn, stitch pattern and tension. The tool scales the swatch's measured consumption to the planned project area and rounds the purchase to complete balls. A garment-size label alone does not capture differences in gauge, cables, texture or fibre.
Compare length and the project's required gauge as well as weight. Two 100 g balls can contain very different metres of yarn. The calculator's pack size is an input for the chosen yarn; changing yarn type does not guarantee that the same project dimensions or fabric will result.
Estimate the project consumption from the measured swatch first, include any explicit allowance, then divide by the chosen ball quantity and round up. Preserve the same units throughout the calculation. An unused part of the final ball is a purchase remainder; it does not imply the swatch estimate or stitch gauge was exact.
Calculation/content reviewed 4 October 2026. Source: Babushka Market’s displayed formulas, units and labelled editable assumptions. How the estimates work
