Underwear can be a good beginner sewing project: the pieces are small, fabric consumption is low, and the result can be tried on and assessed quickly. But a simple-looking design does not mean fabric properties can be ignored. Stretch and recovery, the choice of elastic and the compatibility between the material and the pattern are especially important.
The same pattern cut from two different knit fabrics can fit very differently. For underwear, selecting the correct size and following the fabric recommendations are equally important.
Why Underwear Can Be a Good First Project
Simple briefs have relatively few pattern pieces, use little fabric and provide quick fitting feedback. You can check whether the rise is comfortable, the leg openings sit correctly and the elastic tension feels right. Underwear also teaches useful techniques for working with stretch fabrics.
What You Need
Industrial equipment is not essential. For a simple pair of briefs you can use a domestic machine with a zigzag or stretch stitch, knit needles, polyester thread, scissors or a rotary cutter, pins or clips, suitable elastic, the main knit fabric and a material for the inner gusset. An overlocker is useful but optional. The important point is that the seam retains the stretch required by the garment.
Choosing Fabric
Cotton knit with elastane is comfortable for everyday briefs and is often easy for a first project. Modal and viscose knits are soft and fluid but may be more mobile during sewing. Microfibre and lingerie knits are thin and smooth, although their properties vary considerably. Stretch lace can be used for panels or the whole garment. Powernet and other firm stretch meshes are used where more stability or support is needed.
Do not select fabric by name alone. Two fabrics both sold as “cotton jersey” can differ greatly in stretch and recovery. Test the actual material before cutting.
Fabric Stretch and Recovery
Underwear patterns often use negative ease: parts of the finished garment are smaller than the corresponding body measurements because the fabric stretches to fit.
To check stretch, mark a measured section on the relaxed fabric, for example 10 cm, and stretch it carefully in the required direction. If 10 cm stretches to 15 cm, the stretch percentage is 50%: (15 − 10) / 10 × 100 = 50%.
Stretch percentage alone is not enough. Recovery is equally important. After the fabric is released, it should return as close as possible to its original length. A fabric may stretch well but recover poorly, causing the garment to lose shape quickly.
Choosing an Underwear Pattern
Choose the size from the chart supplied with the specific pattern. Hip circumference is often one of the main measurements for briefs, but follow the pattern maker's own instructions.
In addition to size, check the recommended material, required stretch percentage and direction, seam allowances, elastic type and width, and construction recommendations.
If the fabric stretches less than the pattern requires, do not simply choose a larger size. Likewise, do not automatically size down because the fabric stretches more. It is safer to use material within the range for which the pattern was drafted.
Stretch Direction When Cutting
For underwear, stretch direction is as important as grainline is for many woven garments. Usually the required or greatest stretch runs around the body, but the exact direction should be shown on the pattern or in the instructions.
If the fabric stretches in two directions, determine which direction should run around the body and which vertically. Cutting in the wrong direction can make the garment too tight, cause excessive lengthwise stretch or reduce shape recovery.
The Gusset
The gusset may consist of an outer layer in the main fabric and an inner layer made from a material suitable for direct skin contact. Soft cotton knit is commonly used for the inner gusset because it is absorbent and comfortable.
It does not have to be white: colour does not determine hygiene. The outer gusset does not have to be cotton either and may be cut from the main garment fabric.
Constructing the Gusset
Some designs use the “burrito” method, which encloses the gusset seams inside the garment.
- Match the back piece with the outer and inner gusset pieces according to the pattern instructions.
- Sew the first seam.
- Roll the main garment piece out of the way of the next seam.
- Position the front piece between the gusset layers.
- Sew the second seam.
- Turn the garment through.
The raw gusset seams are enclosed between the layers. The exact right-side/wrong-side arrangement depends on the pattern, so the construction diagram for the specific design is particularly useful.
Construction Order for Briefs
- Cut the front, back and gusset pieces.
- Join the gusset to the front and back using the selected method.
- Sew the side seams.
- Check the symmetry of the leg openings.
- Prepare the elastic or elastic trim.
- Finish the leg openings.
- Finish the top edge.
- Check the stretch seams for skipped stitches or weak areas.
- Press lightly if the fabric and elastic tolerate heat.
The exact order may vary with the design and type of elastic.
Types of Lingerie Elastic
Picot elastic is often used at the waist and leg openings. Plush-back elastic is comfortable against the skin. Fold-over elastic (FOE) wraps around a raw edge and finishes both sides at once. Strap elastic is used for bralettes and similar garments.
When choosing elastic, consider not only width and appearance but also stretch, firmness, recovery, softness and resistance to repeated stretching and washing.
Determining Elastic Length
Universal formulas such as “make leg elastic 10–15% shorter than the opening and waist elastic 5–10% shorter” should not be treated as general rules. The required length depends on the type of elastic, firmness, stretch, shape of the edge, garment fabric, pattern construction and desired level of snugness.
For a professionally drafted pattern, use the length or ratio given by the pattern maker. If no value is provided, test the elastic on a sample and check that it holds the edge without rippling, digging into the body or remaining too loose.
Applying Elastic Evenly
To distribute tension evenly, divide both the elastic and the garment opening into the same number of sections, for example quarters. Match the marks and distribute stretch between them.
Avoid stretching the main knit more than the construction requires. If both the fabric and elastic are stretched excessively during sewing, the edge can become wavy. Picot elastic, FOE and fully enclosed elastic are applied differently, so one method does not suit every elastic.
Common Problems
The elastic edge ripples. Possible causes include stretched fabric, elastic that is too long or too soft, unsuitable machine settings, excessive presser-foot pressure or the wrong stitch. Do not automatically shorten the elastic by a fixed percentage.
Elastic digs into the body. Check tension, elastic length and firmness, garment width, leg-opening height and size. The elastic itself is not always the only cause.
The garment slips or rolls. Possible causes include size, rise, side shape, elastic properties, fabric-pattern mismatch or body shape. Check the garment fit before changing the elastic.
Skipped stitches or broken seams. Check needle type and condition, threading and test on a scrap. If the seam breaks when stretched, the stitch or thread may not provide enough elasticity.
Moving On to a Bralette
A bralette is a more advanced project than simple briefs because support is important as well as fit. Construction may include cups, an underbust section, elastic band, straps, adjusters, lining and stabilised areas.
The band material must match the design. A universal rule such as “make the band 8–12% shorter than the underbust” is unreliable: the same reduction produces very different tension in a soft elastic and a firm supportive material. Band length should be determined by the pattern and the properties of the materials used.
Straps
Adjustable straps use strap elastic, rings and sliders. Strap attachment points depend on cup construction, shoulder shape and the design. If straps slip, check front and back attachment positions, back width, strap length and shoulder shape.
Can You Copy a Pattern from Existing Underwear?
Well-fitting underwear can provide useful information about shape and proportions, but simply tracing it does not always produce an accurate pattern. Fabric stretches during wear, elastic changes edge shape, some areas distort and the new material may have different stretch and recovery.
If you copy an existing garment, use one that fits well, identify seams and construction lines, record the stretch direction, assess the original fabric properties if possible and always sew a test version. Do not automatically add a fixed 5 mm to the side seams just because the new fabric stretches less; the negative ease of the whole construction may need to be reconsidered.
Frequently Asked Questions
How long does a pair of briefs take to sew?
Once the technique is familiar, a simple design can be sewn quite quickly. The first pair takes longer because stretch fabric and elastic are new skills. Accuracy and quality matter more than a promise of “40 minutes.”
How much fabric do I need?
It depends on size, design, fabric width and stretch direction. Simple briefs use a small amount of fabric, but use the requirement information for the specific pattern and remember to include elastic.
Do I need an overlocker?
No. Simple underwear can be sewn on a domestic machine with an appropriate stretch stitch or zigzag. An overlocker speeds up construction but is not essential.
What fabric is best for a first project?
A stable cotton knit with elastane that meets the stretch requirements of the specific pattern is a good option. The key factors are appropriate stretch direction and good recovery, not the fabric name alone.
Can I use lace?
Yes, if the pattern is intended for stretch material and the lace has the required stretch in the correct direction. The inner gusset is usually made from a soft material suitable for direct skin contact.
What size should I choose?
Choose from the specific pattern chart and check that the fabric meets the stated stretch requirements. Do not automatically size down for a stretchier fabric or size up for a less stretchy one.
Where to Start
For a first project, choose a simple brief pattern and material that meets the pattern requirements. Before cutting, check stretch direction and percentage, fabric recovery, elastic properties and size selection.
Sew one test pair and assess it not only immediately after fitting but also after some wear: do the edges dig in, does the garment slip, does the knit retain its shape, does the elastic recover, and do the seams remain elastic?
In underwear, fit depends not only on pattern dimensions but also on the behaviour of the fabric and elastic. Universal percentages and identical adjustments for every material are therefore unreliable.
ERGOMODELS underwear patterns are professionally developed with the properties of the recommended materials in mind. Depending on the design, the pattern information includes the necessary sizing, technical instructions and available digital formats.