Hello from Germany!
I’m searching for help in calculating how much yarn I need to weave a project. I did my last weaving 30 years ago and would like to restart. Thanks for answering and best regards.
—Ingeborg
Hi Ingeborg!
Your calculations will need to include both warp yarn and weft yarn amounts, while taking into account the loom you’re weaving on, the fiber you’re using, and the structure you’re weaving. Since you’re in Germany, you may prefer to make the following measurements and calculations using the metric system, but the principles will be the same.
Start Here
The first bit of information you need to know is your loom waste, beginning with the length of warp that is left over after you finish weaving. It’s the amount used in tying onto or looped around the back apron rod, plus the length from the back apron rod to the fell of the cloth where you cut the woven fabric from the loom. This can add up to anywhere from 15" to 30", depending on your loom’s size and construction.
Add to that the length of warp you used to tie onto the front apron rod, and the length of warp you used up when spreading it out (before you actually started weaving the real cloth). This could be about 10". In Handwoven magazine projects, we allow at least 27" for total loom waste. I think that number is a bit tight, so I usually allow 1 yd for total loom waste in my own projects.
Front loom waste includes the length of the warp that ties onto the front apron rod, as well as the amount used for spreading before the real weaving begins—probably around 10". Photo by George Boe
Next, you have to consider take-up and shrinkage for the yarns and weave structure you’ve selected. I usually allow 10 percent for cottons and other spun yarns that do not shrink very much when woven in plain weave or similar structures. If the yarns shrink a lot or you use a structure that collapses a lot, you’ll need to increase that number. But let's start with 10 percent.
It’s Calculation Time
Say you want to weave a scarf that has a finished length of 63" (plus 2" for hemming, for a woven length of 65"), a width of 8", and a balanced sett of 20 epi/ppi.
To determine the length of warp needed for the scarf itself, add the woven length (65") plus 10 percent of the length (6.5", which we’ll round up to 7"), plus loom waste from the back (we’ll say 26"), plus loom waste at the front (10").
Warp length in inches = 65" (woven length) + 7" (take-up) + 26" (back loom waste) + 10" (front loom waste) = 108"
Warp length in yards = 108" / 36" per yard = 3 yd
To determine the total amount of warp yarn needed, you’ll multiply the number of ends in your warp by the warp length you just computed. In this case, we have an 8-inch-wide warp sett at 20 epi.
Total warp ends = 8" (warp width) x 20 epi = 160 ends
Total warp needed in yards = 160 ends x 3 yds per end = 480 yds
To determine the amount of weft, you need to know the warp’s width and length, and the number of picks per inch. We also need to add 10 percent to the weft calculation to account for weft take-up. For our 8"-wide warp woven at 20 picks per inch to a length of 65", here are the numbers.
Weft needed in inches = 8" (warp width) x 20 (ppi) x 65" (woven length) = 10,400"
Additional weft needed for take-up = 10,400" + 1,040" = 11,440"
Total weft needed in yards = 11,440" / 36" per yd = 318 yd
So there you go: This scarf will require 480 yds of warp yarn, and 318 yds of weft yarn.
But Wait, There’s More!
What if you want fringed ends on your scarf rather than hems—does that make a difference in warp length? Maybe not! You can consider the amount needed for fringe at the beginning of the scarf to come from the part of the warp you used for tying on and spreading the warp (the 10" mentioned above), and the fringe at the end of the scarf to be part of the warp leftovers (the 15" to 30" mentioned above). As long as your planned fringe lengths fit within your front and back loom waste, you can safely ignore fringe as you plan your warp length.
Fringe can often come from loom waste. Photo by Susan E. Horton
I’ll admit that I usually plan my warps a bit differently from the way I just described. Why, you ask? It’s because I don’t like to warp a loom for just one item. As I weave the first piece, I inevitably come up with ideas about how to vary the weft colors or the treadling order to make something even better. So I always put on enough warp for two or more items.
With that thought in mind, let’s reconsider the fringe question. If you’re weaving two scarves on your warp, the first section of fringe can come out of front loom waste, and the final section of fringe can come out of back loom waste. But don’t forget about the two fringe sections between the scarves! If you’re weaving more than one fringed item on a single warp, you’ll need to add warp length to accommodate the fringe sections that fall between the pieces.
I hope this helps!
First published June 1, 2016; updated May 28, 2025