Master The Fly Front Zipper- A Tutorial

Take the Fear out of Sewing Fly-Front Zippers

by Linda Reynolds

Sewing a fly-front zipper seems intimidating. But, it’s actually one of the easiest zipper applications to sew, largely because much of the structural sewing is done behind the scenes on the inside of the garment. The key to a well-sewn fly-front zipper is in the preparation done before any sewing begins.

Spring Sale Master The Fly Front Zipper  A Tutorial

To ensure a fast and easy application, apply the zipper before the front and back sections are joined, while the fabric pieces are still flat. Also take care to properly mark the critical areas of the fly front, and use a zipper that’s longer than the opening to avoid having to sew around the slider mechanism.

A fly-front zipper can open from either the right or left side. For men, zippers always open from the right side. Jeans, whether for men or women, also typically open from the right side. But when it comes to women’s pants, trousers or skirts, the zipper can open from either side.

Use these tips to ensure a successful fly-front zipper application:

• Use a zipper that is longer than the zipper opening.

• Carefully mark the center-front seamline and the zipper base point, usually designated by a square dot on commercial patterns.

• Interface the flaps from the center-front seamline to the flap edges to add body and prevent the material from shifting when the final stitching is done.

• Carefully mark the final stitching line to ensure the stitching is straight.

• Cut off the excess zipper only after the waistline seamline is stitched or the facing is attached. This will ensure the zipper ends neatly and securely at the waist.

While it’s always best to use a pattern designed for a fly-front zipper, adding one to a pant pattern that hasn’t been designed for one is easy.


• Pants pattern without fly-front zipper

• Pattern or tracing paper

• Curved ruler

Tape tissue or craft paper to the pattern center front.

Determine the zipper base point. This will vary based on one’s size, personal fitting adjustments to the front and the style of the pants. Typically, the base point is located anywhere from 2” to 4” from the crotch inseam intersection. There should be enough space to accommodate a 7” or 9” zipper. Once determined, mark the point on the center-front line with a square dot.

Add the flap to the tracing paper by drawing a line 1 3/4” from the center-front seamline that curves to the zipper base point (A), using the curved ruler to ensure a smooth curve. This becomes the new cutting line for the fly front.

MasterFly A Master The Fly Front Zipper  A Tutorial

Cut out the new pattern piece and construct the fly front.

Screen Shot 2018 01 25 at 12.39.32 PM Master The Fly Front Zipper  A Tutorial

 Master The Fly Front Zipper  A Tutorial
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2 Responses to Master The Fly Front Zipper- A Tutorial

  1. Rosanne says:

    All zippers are easy to put in. The secret is putting it in before any other seams are sewn. That means you’ll have to make sure your garment fits before you sew it together. Overall, the invisible zipper is the simplest one, following by the fly-front and lapped. Believe it or not the center application can be tricky because both sides need to be sewed in the same direction to avoid diagonal drag lines on one side.

  2. Linda Morotz says:

    I have made slacks with a fly front zipper so am familiar with it. However, I did enjoy
    reading your above instructions with pictures as it made it sound even simpler. Keep
    up the good informational and fun instructions!! Thank you! Linda 2-13-2018