Button Size Guide: Ligne, Millimetres and How to Pick the Right Size

 Ask a buyer why a bulk button order went wrong, and the answer is often simple: the size was wrong. Maybe the button was too big for the buttonhole, too small to look balanced, or specified in one unit by the designer and read in another by the supplier. Size mix-ups are among the most avoidable trim errors, and they are expensive because they usually surface after thousands of pieces are already made.

This guide explains how button sizing works, gives a conversion chart, and shows how to choose and specify the right size for different garments.

What Is a Ligne?

Button sizes in the garment trade are commonly given in ligne (often written as L), a unit that comes from the French button-making tradition. One ligne equals one fortieth of an inch, which is about 0.635 mm. The larger the ligne number, the larger the button.

Many suppliers and factories still use ligne as the everyday standard, while designers and tech packs often use millimetres or inches. Knowing both avoids confusion when specifications pass between teams.

Ligne to Millimetre Conversion Chart

Ligne	Approx. mm	Approx. inches
14L	8.9 mm	11/32"
16L	10.2 mm	3/8"
18L	11.4 mm	7/16"
20L	12.7 mm	1/2"
24L	15.2 mm	5/8"
28L	17.8 mm	11/16"
30L	19.0 mm	3/4"
32L	20.3 mm	13/16"
36L	22.9 mm	7/8"
40L	25.4 mm	1"

To convert any size yourself, multiply the ligne number by 0.635 to get millimetres. Treat the results as approximate, since real buttons carry small manufacturing tolerances.

Which Size for Which Garment?

These are common starting points. Exact choices depend on design, fabric and brand preference, so always test on a sample.

Garment	Typical ligne range	Notes
Shirt front placket	16L to 20L	Smaller for dress shirts, slightly larger for casual
Shirt collar and cuff	14L to 16L	Smaller buttons for neat detailing
Blouse and kurti	14L to 20L	Keep light and proportionate to fabric
Kurta and Nehru jacket	18L to 24L	Balance visibility with a refined look
Sherwani and bandhgala	24L to 32L	Larger, detailed buttons for visual presence
Blazer front	30L to 36L	Standard for tailored jackets
Blazer sleeve	24L to 28L	Smaller than the front
Jeans waistband	24L to 40L	Depends on style and branding
Coats and overcoats	32L to 40L	Larger buttons for heavy fabric
Kidswear	14L to 20L	Keep smooth, secure and easy to handle

How to Choose the Right Size

Match the buttonhole. The buttonhole should be slightly larger than the button’s diameter, plus allowance for the button’s thickness. A hole that is too tight strains the fabric. One that is too loose lets the button slip open.

Consider the fabric. Light fabrics like voile or georgette look better with smaller, lighter buttons. Heavy fabrics like wool, canvas and denim can carry bigger ones without looking out of place.

Think about proportion. The button should feel balanced against the garment’s scale. A tiny button on a heavy overcoat looks lost, and an oversized one on a delicate blouse overpowers it.

Check the placket width. The button must fit comfortably on the placket with enough edge margin. If the placket is narrow, a large button will crowd the edge.

Use the right size at each position. Many garments use different sizes in different places, such as a larger front button and smaller sleeve or collar buttons.

Size Considerations by Material

Material affects how a given size looks and behaves.

For metal, where a supplier handles Metal Button Manufacturing, a larger button is also a heavier one. A 36L zinc-cast button on a thin fabric will drag the placket down, so check weight as well as diameter. The shank length matters too, since thick fabrics need a longer shank for the button to sit properly.

For polyester, with Polyester Button Manufacturing, thickness and hole size are the key details. Two buttons with the same diameter can differ in thickness, and that changes how they sit and feel. Check hole diameter and spacing, because holes that are too large or too close to the edge weaken the button.

How to Write a Button Specification

A clear spec prevents mistakes. Include these details every time:

• Material: polyester, zinc alloy, brass or another type
• Size: in ligne and millimetres, with a tolerance, for example 20L (12.7 mm, plus or minus 0.3 mm)
• Thickness: especially for polyester
• Hole or shank type: 2-hole, 4-hole, shank, snap or sew-through
• Finish and colour: with a physical sample or colour code
• Quantity: including spares for wastage and replacements
• Packing: pieces per bag or carton

Giving size in both ligne and millimetres removes ambiguity if the person reading the order is used to a different unit.

Common Sizing Mistakes to Avoid

1. Specifying in one unit only. Mixing up ligne, millimetres and inches is a classic error.
2. Ignoring thickness. Diameter is only part of the story.
3. Skipping a sample fit. Always sew a sample on the real fabric and test it through the buttonhole.
4. Forgetting tolerance. Without a tolerance, small variations can become disputes.
5. Not ordering spares. Buttons get damaged during attachment, so order a margin above the exact count.
6. Assuming one size fits a whole collection. Different garments in the range need different sizes.

A Simple Sizing Workflow

1. Decide the garment, fabric and design intent.
2. Pick a starting size from the table above.
3. Request samples in two or three neighbouring sizes.
4. Sew them onto the actual fabric and check fit, look and drape.
5. Confirm the buttonhole size and spacing.
6. Write the final spec with size, tolerance, thickness and finish.
7. Approve a pre-production sample and keep a sealed copy.
8. Measure a random sample from each delivery against the spec.

Why Local Sampling Helps

Sizing decisions improve when you can hold the actual buttons against the actual fabric. Working with Clothing Fastener Manufacturers in Delhi makes it practical to review several sizes in person, adjust quickly and approve the right option without waiting on couriers. For production calendars with tight deadlines, that saved time matters.

Final Thoughts

Button sizing looks like a small detail but has large consequences. Know the ligne system, keep a conversion chart handy, and always specify size in more than one unit. Choose the size based on the garment, the fabric and the buttonhole, then test on a real sample before placing a bulk order.

A correctly sized button sits neatly, closes smoothly and looks intentional. Getting this right at the specification stage costs a few minutes and saves a lot of rework.