Learning how to add seam allowance to your basic blocks 

Adding seam allowance to a basic block or ePattern, in Adobe illustrator, might seem pretty much impossible! This handy tutorial shows you how to add your very own custom seams to your ePattern, once they have been customised. It’s quick, effortless and once you are familiar with the process you can start to define how much allowance you require on each of your finished ePatterns. This is especially helpful when dealing with stretch blocks that use roughly half of the normal seam allowance. This tutorial is an absolute must-see!

What is seam allowance?

Seam allowance is all about personal preference and very much depends on the Sewist and the machinery they are using. Seam allowance is the space or area between the edge of the fabric and the line of stitching, on two (or more) pieces of material being stitched together.

Why do I need seam allowance?

It is the extra material needed to prevent the seam from fraying and eventually coming apart. If a garment is sewn together without seam allowance, it will no longer be the correct size as the line of stitching will encroach into the fit of the garment, therefore making the garment, not the intended size.

Why do ePatterns not have seam allowance?

ePatterns are predominantly used as a template to create new designs or styles, specifically using our online video tutorials. Changing any block to create new styles can alter the block dramatically, therefore, existing seam allowances might no longer be correct, and can become confusing. Typically seam allowance is added to a block or design once all amendments or design elements have been completed and the new pattern is ready to be sewn up for testing or toiling.

What next?

Click the button below to download the multi-page PDF templates.


  1. Veena

    Hai. I would like to learn stiching n cutting class. I am from India. How can I learn with you people. ? Please give me the guidence

    • patternladmin

      Hi Veena, thanks for your comment. Unfortunately, at this time we do not teach sewing classes. Ideally, people that use our software already have some experience with sewing patterns and constructing garments. We do however have courses on pattern cutting which should teach you how to adjust your basic blocks into finished patterns. We have a small selection right now but will be adding more very soon. We are just putting the finishing touches to our new courses and tutorials page. Please sign up to our newsletter, to keep up to date with new products, features, tutorials and more.


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