Figure out how much yarn your crochet or knitting project is likely to need using your actual swatch and yarn.
YarnMath is a free yarn calculator that estimates yarn needed in grams, ounces, meters, yards, and skeins.
1. Start with your preferences
2. Your yarn
Enter the information from your yarn label. YarnMath uses your swatch weight for the main estimate. Skein information lets it show results in familiar yarn quantities.
3. Your swatch
This is the most important part of the estimate. Use the same yarn, stitch pattern, and general tension you plan to use in your project.
Optional: enter your stitch and row gauge
Gauge is useful for checking your swatch, but YarnMath does not need stitch count to estimate yarn consumption when you provide the swatch's physical size and weight.
4. Your project
Optional: add extra yarn for project-specific details
Use this if your project has something your simple dimensions don't fully capture, such as a substantial border, fringe, cables, heavy texture, shaping, or other yarn-hungry details.
How YarnMath works
YarnMath measures how much yarn your swatch uses per unit of surface area, then scales that usage to your project's estimated surface area.
Your chosen safety buffer provides extra yarn for normal differences in tension, finishing, weaving ends, small mistakes, and other variation.
The estimate becomes much more useful when your swatch uses the same yarn and stitch pattern as the finished project.
About YarnMath
YarnMath is a free yarn calculator for knitters and crocheters. It uses the weight and physical size of your swatch to estimate how much yarn a project may require. You can work in metric or imperial measurements and see results in grams, ounces, meters, yards, and skeins.
Because every project, yarn, stitch pattern, and crafter is different, YarnMath provides an estimate rather than a guaranteed yarn requirement. When possible, having extra yarn is always a good idea.
Yarn Calculator FAQ
How much yarn do I need for my project?
Yarn requirements depend on your yarn, stitch pattern, tension, project size, and construction. YarnMath estimates your yarn usage by measuring how much yarn your own swatch consumes and scaling that result to your project's dimensions.
How does YarnMath calculate yarn usage?
YarnMath calculates how many grams of yarn your swatch uses per square centimeter of fabric, then applies that rate to the estimated surface area of your project. A safety buffer can be added to account for normal variation and finishing.
Can I use YarnMath for both crochet and knitting?
Yes. YarnMath can be used for crochet and knitting. The most important thing is to make your swatch with the same yarn, stitch pattern, and general tension you plan to use for the finished project.
Why do I need to weigh my swatch?
Weighing your swatch lets YarnMath measure actual yarn consumption rather than relying on a general estimate. This helps account for differences in yarn, stitch pattern, and your personal tension.
Can YarnMath calculate yards and meters?
Yes. If you enter the length of one skein, YarnMath can estimate the approximate total yarn length needed in meters or yards. You can also switch between metric and imperial measurements for the calculator inputs.