Why prepare fabric before you sew
Fabric comes off the bolt with more going on than you can see. It may hold manufacturing finishes, extra dye, and tension from being rolled tightly. Natural fibers such as cotton and linen can also shrink the first time they get wet (see does cotton shrink in the wash and does cotton linen shrink). Preparing the cloth before you cut means those changes happen before the garment or project exists, rather than afterward.
Preparation is usually a short sequence: decide whether to wash, wash and dry the fabric the way you plan to care for the finished item, press it, and check that the grain is straight.
Should you wash fabric before sewing
For most washable fabrics, many sewists choose to prewash. The decision depends on the fiber, the project and how you intend to launder it.
Reasons to prewash
- Shrinkage. Cotton, linen, rayon and some other fibers can shrink in the first wash. Amounts vary widely by fabric, so the only reliable way to know is to test. Test a swatch to find out how much yours will change (see the swatch test below).
- Excess dye. Some dark or bright fabrics release dye in early washes. Washing first lets you see whether colors run before they can stain a pale piece sewn next to them.
- Finishes. Mills sometimes apply sizing or stiffeners. Washing removes much of it, which can change how the fabric feels and drapes.
- Grain. Water and heat can help the threads relax, which may make the cloth easier to straighten.
When you can skip it
- Dry-clean-only fabrics, such as many structured wools and some silks, are normally not washed. Follow the care label or seller information.
- Items that will never be laundered, such as some decor or craft pieces.
- Pre-cut packs and trims, where washing could cause fraying or distortion. Some makers prefer to leave these as they are.
If you are unsure, test a small swatch (below) rather than guessing.
How to prewash fabric step by step
Prevent fraying
Loosely woven fabrics can tangle and fray in the machine. Before washing, you can finish the cut edges with a zigzag stitch, a serged edge, or pinking shears. Some people also fold the yardage and secure the raw edges loosely. Tangles of thread are easier to avoid than to untangle.
Sort and choose a cycle
- Unfold the fabric and check any care information from the seller or the bolt end.
- Separate dark and light colors. If you are unsure about dye, wash that piece alone.
- Wash the fabric the way you plan to wash the finished item: the same temperature and cycle. This is the guidance repeated across most sewing sources, because it lets the fabric do its shrinking in advance.
- Avoid overloading the machine so the cloth can move freely.
Drying
Dry the fabric in the way you expect to dry the finished item. If you plan to line dry the garment, line dry the fabric. If you will use a dryer, use the dryer. Take the fabric out while it is slightly damp if you can, since that makes pressing easier and reduces creasing.
What should I use for a prewash
Plain water and a mild detergent are enough for most fabrics. Many guides suggest skipping fabric softener and other extras, because softener can leave a residue that affects how the cloth behaves under the iron and needle. If a fabric has a special care label, such as hand wash only, follow that instead.
Press and check the grain
Once dry, press the fabric flat. Use a heat setting suitable for the fiber and test on a corner first; our ironing guide by fabric type lists settings. Then check that the fabric is square:
- Fold the fabric in half along its length, matching the selvages, and see whether the cut edge lines up and the cloth lies flat.
- If it twists or ripples, the grain may be off. Gentle pulling on the diagonal while the fabric is damp can sometimes help, and pressing can set it.
Patterns assume the grain runs straight, so this step affects how the finished piece hangs.
Quick preparation checklist
- Check the fiber content and care information.
- Finish raw edges if the weave is loose.
- Wash and dry the way you will care for the finished item.
- Press out wrinkles.
- Check the grain and square the ends.
- Store prepared fabric folded or on a roll until you cut.
What if you forgot to prewash
If you have already sewn the item, you can still wash it once, preferably on a gentle setting and following the fabric’s care label. Be aware it may shrink or the colors may bleed. For a garment that no longer fits afterward, there is not much to do. For future projects, a swatch test avoids the problem.
A simple swatch test: cut a square of known size, trace it on paper, wash and dry it as planned, then compare it with the tracing. If it has shrunk or changed noticeably, prewash the full piece.
A note on fabric weight (GSM)
GSM stands for grams per square meter, a measure of fabric weight. A higher number generally means a heavier, denser cloth. It can help you compare fabrics, but it does not tell you how a fabric will drape or shrink, so it is a guide rather than a rule for preparation.
Choosing practice fabric
If you are new to sewing, an inexpensive woven cotton such as muslin or plain quilting cotton is a common choice for practice. It is stable and forgiving. If you are considering using it for garments afterward, see whether quilting fabric works for clothing.
Related guides
- Working with stretchy cloth? Read about whether woven fabric is stretchy before you decide how to prepare it.
- Planning to color your cloth? Fabrics should be clean and free of finishes first, as covered in our dye bath guide.
Frequently asked questions
How do you prepare the fabric before sewing?
Wash and dry it as you plan to care for the finished item, press it flat, and check the grain before cutting.
How do you prewash fabric without fraying?
Finish the cut edges with a zigzag stitch, serging or pinking shears before washing, and avoid overloading the machine.
What fabrics should not be washed?
Dry-clean-only fabrics, such as many structured wools and some silks, are generally not washed. Check the care label or ask the seller.
What are the five steps in sewing?
Sources describe them differently. A common outline is: choose the pattern and fabric, prepare the fabric, cut, sew, then press and finish.