Here's a Step-By-Step Guide to Sewing a Flawless French Seam

Fabric folded in half

When you’re working with lightweight, sheer fabrics, there’s a sense of airiness and elegance to them. Which means they deserve an equally-as-elegant finished seam that hides all your raw fabric edges. Enter the French seam. Keep reading to learn how to sew it.

This particular finish gets a bad reputation for being tough to execute, but it’s easier than you might think. The big thing to remember is that instead of sewing your right sides together (which you do in nearly every sewing project), your first seam is sewn wrong sides together. Once you have that slightly-backward process down though, it’s smooth sailing!

Whether you’re sewing together a breezy blouse or finishing an unlined jacket, here’s how to perfectly sew a French seam.

How to Sew a French Seam

Level: Easy

What You Need

  • Fabric
  • Sewing pins
  • Iron
  • Scissors or a rotary cutter


1. Determine Your Seam Allowance

Look at your pattern to determine the seam allowances it calls for. Subtract 2/8″ (aka ¼”) from that number. (So if yours is ⅝”, your number is ⅜”) This will be the seam allowance for your first seam.

Pro Tip: If you don’t want to do math, you can also line the left side of your presser foot up with the seam allowance that your pattern calls for. (On most machines, this will be ¼”.)

2. Pin and Sew Your Seam

Pinned fabric

Pin your fabric wrong sides together and place under your presser foot at the ⅜” seam allowance (or whatever number you calculated in step 1). Sew the entire seam.

3. Trim Seam Allowance

Cutting fabric

Trim the seam allowance down to ⅛”.

Pro Tip: If you’re working with lightweight fabrics that easily shift (hi, chiffon), pin a point on the seam to an ironing board or another pin-able surface. Go directly through the seam line, leaving the pin sticking up like a tack. Pull the whole seam taut. This will make it easier to trim close to your stitches; the closer you get, the more delicate your finished seam will be.

4. Press the Seam

Ironing the fabric

Open the seam with the right side facing up, so the seam allowance is on top. Set the iron to the correct heat for your fabric type. Press to one side.

Ironing the other side

Turn your fabric over and press on the wrong side so the seam lays completely flat.

5. Prepare to Sew the Second Stitch Line

Ironing the fold line of the fabric

Fold the fabric on the seam, right sides together. Press the seam flat again with the stitching on the edge of the fold.

6. Pin the Second Seam

Pinning the fabric

Pin the layers together on the stitching line if needed. As you become more experienced, you may find that you no longer need to do this and can skip this step.

7. Sew Second Seam

Sewing the fabric

Insert the seam under the presser foot. Sew until your project’s seam allowance equals the number you calculated in step 1. Example: If you sewed at ⅜” and the seam allowance is ⅝” , that means you should sew this step at 2/8” or ¼”.

Good to Know:As you sew, the seam allowance of the first seam will become enclosed within the fold/seam allowance of the second seam.

8. Press Again

Ironing fabric

On the wrong side of the fabric, press the entire French seam to one side.

Ironing the other side of the fabric

Turn your fabric over and press one more time on the right side.

Photos by Marni Weaver.
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35 Responses to “Here’s a Step-By-Step Guide to Sewing a Flawless French Seam”

  1. G.Lee

    Wonderfully clear instruction by word and illustration. Thanks, I think I can handle it now!

  2. Hannah

    Thank you CathyE- very detailed instructions. Love the step-by-step explanation. Much appreciated

  3. CathyE

    Take this seam finish one step further. Add Step #9: Top stitch on right side 1/8″ from seam on side where seam was pressed over. Now you have a finely finished, flawless seam.

  4. Kathryn

    Beginner at sewing here 😊
    Thank you for this clear and easy explanation. Much appreciated!

  5. Katherine Gonzalez

    Thank you! Finally an explanation for how to make French Seams!

  6. Patricia

    I am so happy with all your instructions and demonstrations, clearly and understandable. Cant wait to start.

  7. Nataliya Duka-Farley

    Wouldnt it be much better if demonstrate on plain fabric instead for patterned?

  8. Kathryn Osmond

    Excellent instructions. I tested on a scrap, and the seam came out great. Thanks.

  9. Tava Bubier

    I think I’d be able to get your help when needed. I’m bed bound & trying to sew agaier a very

  10. mrshankbot

    Finally an explanation that makes sense!!! I have my upcoming judged garment competition in the bag, Thank you!

  11. Beverly Norman

    Thank you! You’ve made French Seams so easy to understand by your clear explanations and illustrations. I’ve sewn for many years and have even made wedding gowns for others, and my own wedding gown. I’ve tried French Seams before, and your directions made it easy! Thanks so much!

  12. Lynne hull

    I’ve tried to understand the french seam method but, I’ve just finally got it by watching the diagrams I’m so happy thank you ..

    • Teresa Ribas

      Conheço este ponto desde muito jovem quando a costureira que vinha cá a casa fazer os lençóis para o s enxovais mas com o nome de costura inglesa.