Calculating the cost of materials for a knitting or crocheting project is a little more complex than calculating soap material costs. Because there’s not a recipe. Your pattern may say 150 grams of a specific yarn, but you don’t use exactly 150 grams. You use what you use, and whatever is left over is left over.

As with soap oils, the price per skein of yarn may include a tax or shipping component. You can follow the same process to determine the yarn as a percentage of the order weight for prorated shipping and the yarn cost as a percentage of the order cost for prorated tax.

With yarn projects, though, you need to know how much yarn actually went into the project. How? Weigh the skeins. Weigh them before you use them or just accept the manufacturer’s weight as accurate. If you’ve got a little kitchen scale, weigh the yarns when you finish using it on the project (this assumes you don’t concurrently use the same yarn on multiple projects!). The difference is the amount of yarn in the project. You can then calculate the percentage of the yarn which was used ( (weight at start – weight at end) / weigh at start). The material cost is that percentage of the yarn cost (price per skein * number of skeins used). Add up the material cost for each yarn in the project, and you know the material cost for the project.

A spreadsheet is good for these sort of repetitive calculations. You can estimate a project’s total cost by entering 0 into column ‘G’ and basing column ‘C’ on the pattern’s yarn requirements.

The spreadsheet allows you to check out how different yarns will impact the project material cost too – what happens if I use a more expensive yarn? It’s nice to know before looking at your shopping cart total in absolute shock 🙂