Although buttons were primarily used for fastening, their early use was actually not that functional. Early buttons were used as seals, ornaments, and decorative accents, and it was only in the 13th century that functional buttons as we know them today became fashionable.

Today's modern clothing buttons are generally classified according to:

Button Size - Ligne Number
Button's Material
Loving The Way The Button Is Attached To The Garment
Button Production Technique
Last Use of Button

Classification According to Button Length - Ligne Number

Its number (expressed as “L” next to a number 12L, 14L, 16L, etc.) is the unit of measure used for buttons; refers to the diameter of a button. The larger the ligne number, the larger the button.

One ligne equals 0.635 mm or 0.025 inch. Using this figure, a 12L button has a diameter of 7.62mm or 0.30in, while a 50L button has a diameter of 31.75mm or 1.25in. The ligne number may be an unfamiliar unit of measurement to many people, but it can be easily calculated when you convert it to millimeters or inches. For more information on calculating ligne numbers, please see this post How to Calculate Button Size with Ligne.

Among common button sizes

12L (usually used on button-down shirts),
16L and 18L (both button sizes seen on collared shirts)
Available in 24L (for trousers).

Other buttons larger than these are generally not used for fastening purposes, but are only attached for decorative reasons.

Button Types According to Button's Material

Buttons can also be classified according to the type of material they are made of.

Horn Buttons: Animal horns used to be a traditional button material. However, synthetic horn made of plastic is now more commonly used in buttons.
Metal Buttons: Metal buttons are often seen on leather and denim garments such as jeans and jackets.
Fabric Covered Buttons: It is a necessary material for cloth (or “dressed” as it is commonly called). Such buttons are often used or covered using the fabric itself .
Plastic Buttons: Plastic is inexpensive and easy to manufacture. That is why they are the most common button material in the world (eg polyamide, polyacrylonitrile, polyester). Plastic buttons, which you can find everywhere, are used for both functional and decorative purposes.
Wooden Buttons: Wood is inexpensive but has a short lifespan. Wooden buttons are rarely used for functional purpose. Such buttons are usually used only for decoration.

While those mentioned above are the most common, seashells, coconut shells, pearls, glass, leather, ceramics and vegetable ivory are also other materials produced as buttons.

Classified by How the Button Is Attached to the Garment

There are also special types of buttons that are classified by the way they are attached to the garment.

For example, a flat or sew-on button (also called a hole button because it can come in two- or four-hole types) is attached to a garment by threading it through the holes in the button.

Behind a foot button is a protruding fastener where the thread attaches.

Snaps and snap buttons, commonly found on jeans and leather garments, have a different method of fastening. Rivets (rivets) are used for decorative purposes. They come in two pieces: one piece pierces through the garment, while the second piece holds the other in place. Once attached, the rivet stays closed permanently. Snap buttons attach directly to the fabric. They can then be snapped together and reattached by pressing them together or pulling the two pieces apart.

Classification According to Button Production Technique

Different kinds of buttons, electroplating, spray painting, screen printing, etc. subjected to different production processes such as

For example, some buttons are electroplated to give them a metallic look and feel. Antique coated buttons are designed with a burnt effect for ornamental purposes. Nylon buttons are malleable and have strong plasticity and therefore can often be manufactured to a customer's specifications and required customization.

Classification by Last Use of the Button

Another classification system is the classification of buttons by end use. For example, jacket buttons are normally attached to a shirt, etc. It's very different from the buttons you'll find on it. Other buttons of this type include cardigan buttons, cufflinks, jacket buttons, jacket buttons, jeans buttons, suit buttons, shirt buttons, and others.