Sewing & Pattern making Terms

Seam allowance

In the world of sewing, precision and accuracy are key to creating beautifully constructed garments. One important concept that seamstresses and pattern makers must understand is “seam allowance.” In this article, we will explore the meaning and significance of seam allowance, its role in garment construction and why it is a vital consideration for achieving professional sewing results.

Seam Allowance Demonstration
In this example, the seam allowance is marked as a dashed line

What is a “Seam Allowance”?

Seam allowance refers to the extra space or fabric provided beyond the stitching line, between the raw edge of the fabric and the intended finished edge of the garment. It acts as a buffer zone that allows for seam construction, adjustments, and finishing techniques.

The Role of Seam Allowance: Building Strong and Polished Seams

Defining Seam Allowance:

Seam allowance is the additional fabric provided beyond the stitching line. It ensures room for stitching, finishing, and adjusting garment fit.

The Purpose of Seam Allowance

  1. Stitching Space:

Seam allowance provides a designated area for sewing stitches, preventing them from encroaching on the garment’s edge. It allows for secure and even stitching, reducing the risk of fabric distortion or unraveling.

  1. Fit Adjustment:

Seam allowance offers flexibility for making fit adjustments during the sewing process. It allows for alterations such as taking in or letting out seams to achieve the desired garment fit.

  1. Finishing Techniques:

Seam allowance provides room for various finishing techniques, such as seam finishes, edge treatments and hemming. It enables the incorporation of methods like serging, zigzag stitching or French seams to prevent fraying and add durability.

Standard Seam Allowance Measurements

  • Seam allowances can vary depending on the pattern, fabric type and personal preferences.
  • The most common standard seam allowances are ⅝ inch (1.6 cm) and ⅜ inch (1 cm).

Seam Allowance Considerations

  1. Pattern Instructions:

Follow the pattern instructions to determine the recommended seam allowance. Patterns often include specific seam allowances for different areas of the garment.

  1. Fabric Type:

Different fabrics may require adjustments to the seam allowance. Thick fabrics may benefit from wider seam allowances, while delicate fabrics might require narrower allowances to reduce bulk.

  1. Personal Preferences:

Experienced seamstresses and pattern makers may choose to customize the seam allowance to suit their sewing style and preferences. Some may prefer wider allowances for ease of alterations, while others opt for narrower allowances for reduced bulk and a more precise fit.

Seam Allowance Techniques

  1. Marking:
  • Transfer the seam allowance onto the fabric using pattern markings or tailor’s chalk.
  • Ensure accurate and consistent markings for precise sewing.
  1. Cutting:
  • Cut the fabric along the cutting line, which is typically the edge of the pattern piece, including the seam allowance.
  • Use sharp fabric scissors or a rotary cutter for clean and precise cuts.
  1. Stitching:
  • Sew along the stitching line, which is typically marked on the pattern.
  • Ensure that the seam allowance remains consistent and even throughout the sewing process.


Seam allowance is a vital element in sewing and pattern making, allowing for clean and durable seams while providing room for adjustments and finishing techniques. Understanding the purpose and measurements of seam allowance empowers you to create well-constructed garments with professional-looking results. By incorporating proper seam allowance techniques into your sewing practice, you can elevate your skills and achieve beautifully finished projects that fit and flatter with precision.


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Melissa Villegas
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