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Weaving Calculator - How to Calculate How Much Yarn You’ll Need

As you set out to design your own weaving project, you may be wondering how many yards of yarn you'll need for your project. This will depend on many factors such as your warp sett (or EPI), your loom waste, the finished length of your piece, the finished width, and any additional warp you will need for sampling or fringe. Lucky for you, we've developed a free, easy calculator to help you out. Simply enter the details mentioned above and it will calculate your total warp length and how much total weft yarn you'll need.

 If you're a new weaver and are mystified by any of these terms, scroll down past the calculator and we'll help you out!


Leaving Room for Sampling

While everyone wants to get right into weaving, sampling is a big part of the creativity of a new weaving project, and can save you time, money and heartache by discovering what works and doesn’t work before you weave your entire project. The amount of warp you designate for sampling is ultimately up to you, but we recommend allowing for at least a few inches.

Loom Waste

This will vary depending on the type of loom and how much yarn is lost to the warping process (there's a bit of a learning curve here for beginners). To calculate your loom's waste, take careful notes the next time you weave a project! Warp and thread your loom as you would for any other project. Weave the warp from start to finish, stopping when the warp is close enough to the shafts (or heddle on a rigid heddle loom) that you are no longer able to get a clean shed and continue weaving. Cut the warp off your loom, and measure the extra yarn left at the beginning and end of your project that you weren't able to weave on. This is typically called "loom waste" although this yarn can be used as your fringe. Once you know your loom's average loom waste, you can use this number moving forward. We recommend adding a bit extra to this number just so you have some breathing room at the end of your warp.

If you don't know what your loom waste is and are not sure how much to plug into the calculator for the first project, we recommend using 30" to start with. Most looms have a 20" - 30" length loom waste.

Warp Shrinkage & Take-up

Warp shrinkage will depend on your yarn, and warp take-up will depend on your picks per inch (PPI). If you're not sure, 10-15% is a good rule of thumb.

Finding Your EPI/Sett

To use this calculator, you will need to know your warp sett, or EPI. We have a helpful blog post to help with this, Calculating WPI, EPI, and Sett.

Picks Per Inch

A balanced weave, where both warp and weft threads are equally visible, typically has an EPI and PPI that are close to each other if you are using the same yarn in warp and weft. If you want your weaving to be weft faced, meaning your weft threads are more visible than your warp threads, you will want your PPI to be significantly higher than your EPI. For a warp-faced weaving, you will want a PPI that is significantly lower than your EPI.

Weaving Take-Up

The general rule of thumb is about 10% for balanced weave, and higher for weft-faced weavings.


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