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Weft and Warp Difference : Loom Yarn
Posted on: 18 Mar, 2019


What is the difference between the weft and warp ?

My favorite part of weaving is choosing yarn. There are a wide variety of sizes, colors, textures and fibers to choose from and every project can vary based on the weaving materials used. When you are first learning how to weave, you may wonder which yarn to use and how to use the yarn in your project.

If want to start weaving, but you do not have a loom yet, you can follow my cardboard loom tutorial by following this link to “How to make a cardboard loom” post.

This post contains information about yarns, but you can find more about the types on the Types of Yarns page.

Weaving Basics

There are different kinds of looms used to weave fabric and other woven projects. A loom is used to organize and hold the yarns of a woven project. Two sets of yarn are interlocked in the weaving process- the yarn used to keep the structure of the woven piece and the yarn used to decorate. These two sets of yarns are called the warp and the weft. Below is an explanation between the two.

(You can find more information about looms in the blog post “What is the difference between knitting and weaving?” in the tools section.)

What is the warp?

The warp is a set of yarn vertically wrapped around the loom and it remains in place during the entire weaving process. It gives the structure to the woven project. The warp is later removed off the loom when the woven project is finished.

weft and warp difference loom yarn

What is the weft?

The yarns you use to weave horizontally through the warp are called the weft. Yarns give character to a project. You can create vivid patterns with color and texture to your weaving with yarns of different fibers.

weft and warp difference loom yarn


Take a look at what you are wearing right now. Look at the woven pattern. You may notice the color, design, or the tightness of the material. The ply, material, and density of the fibers play a role in this. When selecting yarn or thread for a project, consider the desired density first– how compact do you want the yarns to be in a woven piece?

Yarn Ply

Most balls of yarns and yarn/thread cones have their size and weight labeled. The thickness of the yarn/thread is adjusted by the ply size.

Plies are individual strands of spun fiber. Plies can be spun thick or thin. After a ply is spun, it can be spun with other plies or remains on its own. But the number of plies that a yarn has cannot be the judge of the thickness of the yarn. For example, a single ply can be spun as thick as a 6-ply stand of yarn.

When considering the project size or area, you must calculate the thickness of the yarns. The thinner the yarns/ threads are the more loops and or rows will need to be made. The thicker the yarns/ threads are the fewer rows will need to be made.

This also affects the time needed to create the project. Thicker yarns/ threads cover an area quicker than thinner yarns/ threads.

How much yarn does my project need?

 EPI, or ends per inch, are the number of threads in one inch of the woven fabric. You can find the EPI of yarn by wrapping a strand around a ruler for one inch.  This affects the density of the warp and how you wrap your loom set.

What is a sett?

A sett is the number of EPI that will be used to wrap a frame loom, and thread a reed. The reed is used to space out the yarns and keep the structure of the width of the woven project. (For more information about the parts of the loom, check out my blog post, “Parts of a Loom”. It will be released in the following weeks.)

You must consider the density of the woven projects – the higher the EPI, the higher the density. When weaving, you must consider how dense the pieces will be. It also dictates how much material you will need.

Yarn Choice

“What kind of yarn should I use for weaving?”

Well, it depends on what you are going to create. Woven material can be used for countless projects; therefore you should use the appropriate material for this project.

 Type of project

The type of project you create influences the number of yarns used and the weaving methods used. Some projects require more pressure than other. For example, when weaving a tapestry, a lot of pressure is used to cover the warp yarns and create images and patterns. However, when weaving a scarf, the pressure can vary and it can be woven loosely.

How to choose the best warp yarn for weaving?

A best way to check the stability of the the yarn is with a yarn strand test. Think of the warp yarns as the skeleton of the weaving project. Therefore, it must remain structured.

 Yarn strand test

While weaving, the yarns cross and rub against each other, in addition to being pulled to keep the tension of the project. Therefore, the stability of the yarn is to be tested. To do this,

1. Grab a small section of the yarn with two hands. Take your fingernail and rub it along the small section. If the material sheds a lot or does not hold its form well, then this yarn is not good as the warp.

2.Also, check the strength of the yarn. Hold a section of yarn and pull on the ends. If the yarn stretches or expands too much, it is not ideal for the warp either. If the yarn breaks or unravels, it too is not ideal as the warp.

Note: Now, this is not to say that you cannot use these yarn as warp, rather it may be difficult to manage if you are just beginning weaving. If you are a more experienced weaver, you might be comfortable using more flexible or delicate yarns as the warp.

While weaving, the tension is kept by the collective yarns and not by just one strand (as in the strand test). The pressure is evened out. Therefore, weaving with a delicate warp yarn is possible.

Warp yarn options

Cotton, wool and jute (linen) is used often for the warp. These fibers are strong and there is a wide variety available.

Some commonly used are:

ply cotton linen

2 ply cotton

(un)mercerized cotton – this is cotton with coating, which strengthens the yarn and gives it a shiny look

Wool and alpaca are also strong and diverse fibers, which can be used as a warp.

Warp color

I tend to prefer a neutral warp when weaving; however experimenting with colorful warps can give your woven project even more character and an interesting look.

Here are a few color ideas for the warp:

1.Neutral colors– Play it safe with basic neutral colors. Neutral colors can also make a statement by contrasting with a darker or lighter weft.

2. Complimentary colors ( yellow/ purple, red/ green, blue/ orange)- Complimentary colors naturally make each other pop out.

3. Monochromatic colors (gradation of one color by adding darker and lighter tones) – these colors are in the same color family. These colors create depth.

4.Neon or bright colors – Neon always pops out, especially on cloth!

5.Mixed-up warp- If you really want to mix it up, try using a warp with two or more colors (or even textures) of yarns. This creates another visual focus.

How to choose the best weft yarn for weaving?

Weft yarn gives you the freedom to create with whatever material you like. Whether it is with yarn, thread, or other materials, such as paper and plastic. Once the warp has been set, your weft is up to you.

The most commonly used weft yarns :

cotton           polyester

linen              acrylic

wool alpaca

 I have found that mixing up yarns with different texture, thickness, and patterns create something interesting. Playing around with inconsistencies in a woven pattern or adding a color point can give your project some flare. For more information about the yarns, you can visit this website’s page, Types of Yarns.

For example, in my next project, I will use these 4 yarns in the weft. Although they are the same color, they have different plies, thickness and made of different material.


As mentioned above, the design of your piece is not only influenced by one aspect, but by everything: the material, density, color and pattern. It takes time to develop an understanding of the materials. So I encourage you to just experiment with as many type as you can and find what works best for you.

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