Seam Allowance

Table of Content

What is Seam Allowance?
Why is Seam Allowance Important?
How to Measure Seam Allowance
Sewing with Seam Allowance
Using the Sewing Machine Seam Guide

1. What is Seam Allowance?

Seam allowance is the distance between the edge of the fabric and the line of stitching (seamline or seam stitch line). Seam allowance is essential for ensuring that pieces fit together correctly and provides excess fabric for efficient sewing

2. Why is Seam Allowance Important?

Stability: The raw/cut edge of fabric has a high chance of fraying with the slightest pressure. Allowing enough fabric between the edge helps maintain the structural integrity of the piece, especially with heavier fabrics.
Fit: The seam allowance can affect the final fit of the garment. Too small a seam allowance may lead to seams that are not secure or that unravel.
Finishing: A larger seam allowance can accommodate adjustments, allowing you to let out or take in seams as needed.

3. How to Measure and Sew with Seam Allowance

When you beginning a new sewing project, always check what the seam allowance is. Most commercial sewing patterns indicate the recommended seam allowance on the pattern itself. If you are creating your own sewing pattern from scratch after you created the pattern you will then add seam allowance to your pattern as the final step. It is important to know how to identify, measure, and sew with seam allowance to ensure your final project comes out as expected.

A. Measuring and Marking Seam Allowance with a Ruler

Determine the Seam Allowance (1/2inch seam allowance): As a reminder, seam allowance is the distance between the raw/cut edge the fabric and the stitch line. For this example we be using a seam allowance of 1/2inch.
Measure 1/2inch with a ruler: Using the ruler measure 1/2inch away from the raw/cut edge of the fabric. For this part using a transparent ruler will be better because you can line up the
Mark the seam allowance.
Use a ruler or seam gauge: This will help you measure and mark the seam allowance accurately.

2. Marking Seam Allowance

Tailor’s chalk or fabric marker: Use these to mark the seam allowance on the fabric.
Create a seam allowance guide: If you’re often sewing the same seam allowance, consider creating a guide. Cut a piece of cardboard or use masking tape to mark your seam allowance on the machine’s throat plate.

3. Sewing with Seam Allowance

Using Your Sewing Machine

Align fabric: Place the edge of the fabric against the sewing machine's seam guide. Most machines have markings (usually in inches) that indicate where to align the fabric edge for specific seam allowances.
Presser foot: Ensure your presser foot is in place and your fabric is aligned properly. The inside edge of the presser foot often corresponds to a standard seam allowance (like 1/4 inch or 1/2 inch).
Sewing: Begin sewing, maintaining a consistent pace. Keep the fabric aligned with the seam guide markings to ensure an even seam allowance throughout.

5. Adjusting Seam Allowance

If your project requires alterations:

Letting out: If you need to make a garment larger, you can gently unpick the seam and add resew the seam with a lesser seam allowance. (Ex. Your shorts are to small and you want to widen them. The initial seam is 1/2”. To “let them out” you will seam rip your seam and resew your shorts at a 1/4” seam allowance)
Taking in: If you need to make a garment smaller, you can resew the seam with a higher seam allowance. (Ex. Your shorts are to wide and you want to make them more narrow. The initial seam is 1/4”. To “take them in” you will resew the seam with a higher seam allowance of 1/2”)

Using the Sewing Machine Seam Guide

Most sewing machines come with built-in seam guides on the throat plate. Here’s how to effectively use them:

Step-by-Step Guide

Identify the Seam Guide: Look for the markings on your machine’s throat plate. These are usually indicated in inches or millimeters.
Setting Up:

For a 1/4 inch seam, align the fabric edge with the guide that corresponds to this measurement.
For a 1/2 inch seam, look for the corresponding guide.

Starting the Seam:

Lower the presser foot and ensure that the fabric is aligned with the seam guide before starting to sew.

Maintaining Consistency:

Keep the fabric edge in contact with the seam guide as you sew to maintain a consistent seam allowance throughout your project.

Use a Seam Guide Foot: If you frequently work with specific seam allowances, consider using a seam guide foot attachment, which has a guide built into the foot itself.

Tips for Seam Allowance Success

Practice on scraps: If you’re unsure about your seam allowance, practice on fabric scraps to build your confidence.
Use a walking foot: For thicker fabrics, a walking foot can help prevent shifting, ensuring a more accurate seam allowance.
Adjust tension: Ensure your machine's tension settings are correct for the fabric type to prevent puckering along the seam.

Conclusion

Understanding and effectively using seam allowance is crucial for successful sewing. By following this tutorial, you'll be able to achieve neat, professional seams every time. Happy sewing!

. Common seam allowances include:

1/4 inch: Often used for quilting.
3/8 inch: Common in garment sewing for lightweight fabrics.
1/2 inch: Standard in home sewing patterns.
5/8 inch: Widely used for most garment sewing patterns.

Seam Allowance: What is it and How to Measure it, and How to use it