Once you’ve determined how much yarn you’ve actually got, you still need to figure out how far you can make it stretch. Will it be enough for the project you’ve envisioned? If not, where are the boundaries of what’s possible? That’s what this next calculator is all about. (If you haven’t yet determined your yards or meters on hand, check out this blog post for instructions and calculators that will help you do that. It might be helpful to print out the results or keep that window open while you start to work with this calculator.)

To use this calculator, you need a few pieces of information: yarn available, and warp length, warp width, and sett. The yarn available is always necessary but the other three are not all required for every application, and you can work within a range of possible values for each. If you enter only a single value (in the minimum field) then that’s the value that will be used in the calculations. If you enter a second, higher value in the maximum field, the sliders at the bottom of the calculator will be able to move up and down between these two end points. Moving them back and forth (or using the arrow keys to change the values up and down or left and right) will show you how each slight change affects the total yarn required. In all cases, the calculator compares yarn required to yarn available and lets you know if you have enough. (FYI: there’s a metric version below the imperial one.)

Here are the kinds of things you can figure out with this calculator:

How long can I make my warp?

Say you’re making placemats, you plan to use a sett of 20 EPI, and you want the warp to be 14″ wide in the reed. How long can your warp be?

Enter the yards you’ve got available at the top and your warp width and chosen sett below, and the calculator will tell you how many inches long you can make your warp.

How wide can I make my warp?

Say you’re making a scarf and plan to make the warp 4 yards long. How WIDE can you make it, assuming a sett of 16 EPI? What if you make it 15 EPI instead? Or 18?

Enter the yards you’ve got available at the top, the length of the warp below, and the minimum and maximum setts (15 and 18) into those fields. The calculator will tell you the maximum width at the bottom, for whatever sett in the range you’ve got selected with the slider.

How wide a stripe can I make with a particular colour?

This is the same problem as above, except that you’re considering only a stripe rather than the entire warp. Again, you’d enter yarn available of the given colour, the warp length and the sett. At the bottom, the calculator will list the maximum width possible given that sett. Note that this “stripe” doesn’t have to be a single stripe. If your maximum width is 10″, you have enough to make one stripe 10″ wide, or two stripes 5″ wide, five stripes 2″ wide, or any number of stripes as long as their total width doesn’t exceed 10″.

How many ends can I get from a single ball of yarn? How many stripes 10 ends wide can I make?

This is still the same problem, except that sett isn’t taken into account. Enter the yards or meters available and the warp length and the calculator will still tell you the number of ends possible. (It can’t calculate how wide that will be without a sett.)

What’s the biggest piece of fabric I can make from the yarn I’ve got?

Say you’ve got several spools of 8/2 cotton, adding up to one pound altogether and want to make tea towels with it. Assuming you need as much for weft as you do for warp, that leaves half a pound, or 1680 yards, available for warp. Let’s also assume you’re going to weave them in twill at 22 EPI. How many towels can you make and how big can they be?

In this case, both warp width and warp length are adjustable. Pick an acceptable range for width (for instance, 20-25″) and enter your sett. The calculator will tell you that, at 20″ wide, your warp can be 137″ long. Assuming you need 24″ for loom waste, that leaves you with 113″, which is enough to make four towels 28″ long, or three towels 36″. If you bump the width up to 25″, the maximum warp length would be 109″, or 85″ after loom waste. That’d make three towels 28″ long or two at 36″.

Once you settle on a size, though, you’ll still need to figure out how to distribute the various colours of 8/2 to make up the width. At that point, you’d be back to calculating how many ends or how wide a stripe are possible, as described previously.

Using the sliders

The last example demonstrates the power of the sliders. Instead of entering just a single number (in the minimum fields), you can enter a range of possible values for the warp length, the warp width, and the sett by putting a second, larger number into the maximum fields. You can make one, two, or all three parameters adjustable. This makes it possible to fiddle with them on the fly, to figure out how to maximize the yarn you’ve got available.

Keep in mind, however: Once you come up with a combo that works with the numbers, you’ll need to evaluate whether they make sense for the project. If your scarf will be 4″ wide in the reed, will you wind up with something you can actually use? If the warp is only 60″ long, after loom waste and dimensional loss, will it still be a length you can wear? If you can only get the width and length you want by making the sett 4 EPI, does that make sense given the yarn you plan to use?

Without further ado, here’s the calculator (imperial first, metric below).