How to Measure Snap Button Size - Complete Guide

Understanding snap button sizes is essential for garment manufacturers, fashion designers, and DIY enthusiasts. The sizing system used in the textile accessories industry can be confusing at first, but once you grasp the basics, choosing the right snap button becomes straightforward. This comprehensive guide covers everything from the ligne measurement system to practical tips for matching snap button sizes to your specific fabric and application.

What Is the Ligne (L) System?

The ligne (abbreviated as "L") is the traditional unit of measurement used in the button and snap button industry. One ligne equals approximately 0.635 millimeters. This system originated in France and has been the global standard for button sizing for over two centuries.

To convert ligne to millimeters, simply multiply the ligne value by 0.635. For example, a 20L snap button measures approximately 12.7mm in diameter.

Snap Button Size Chart: Ligne to Millimeter Conversion

How to Measure a Snap Button

Measuring a snap button correctly is crucial. Here's how to do it:

• Use a caliper or ruler: Measure the diameter of the cap (the visible top part) across its widest point.
• Measure in millimeters: Convert to ligne using the chart above, or divide the mm value by 0.635.
• Don't include prongs or posts: Only measure the cap diameter — prongs, studs, and posts are not included in the size specification.

Choosing the Right Size for Your Fabric

The weight and type of your fabric determines which snap button size works best:

Lightweight Fabrics (Cotton voile, silk, chiffon)

Use smaller snap buttons: 10L to 16L. Lightweight fabrics cannot support heavy fasteners. Prong snap buttons work well because they grip thin fabric effectively without tearing.

Medium-Weight Fabrics (Poplin, twill, denim shirts)

Choose mid-range sizes: 18L to 24L. This is the most common range for everyday garments. Both spring snap buttons and prong snap buttons perform well at these sizes.

Heavyweight Fabrics (Canvas, leather, denim, outerwear)

Go with larger snap buttons: 24L to 36L. Heavy materials need strong, visible fasteners. Stainless steel snap buttons are ideal for outdoor and workwear applications that demand durability.

Snap Button Size by Application

Tips for Ordering the Right Size

• Request samples first: Always test snap buttons on your actual fabric before placing a bulk order.
• Consider the cap style: Flat caps appear smaller visually than domed or ring-spring caps of the same ligne size.
• Check machine compatibility: Your fastening machine mold must match the snap button size — a 15mm mold cannot set a 12.5mm snap.
• Account for fabric thickness: Thicker fabrics may require longer posts or studs to ensure secure fastening.
• Order extra: Include 5-10% overage for production waste and quality testing.

Common Sizing Mistakes to Avoid

• Using oversized snaps on baby clothes: Large metal closures pose choking hazards and fail safety tests.
• Ignoring prong length: Short prongs on thick fabric won't grip properly, leading to snap failure.
• Mixing sizes across a garment: Front closure snaps and pocket snaps can differ in size, but should match in style and finish.

Conclusion

Choosing the right snap button size ensures both functionality and aesthetics in your garments. Use the ligne conversion chart as your reference, always test on your actual fabric, and don't hesitate to contact our team for guidance on matching the perfect snap button to your project. Ata Buttons offers a complete range of snap buttons from 10L to 36L, all manufactured in Istanbul, Turkey with custom logo options available.