Packaging Thread Guide: 18/410, 20/410, 24/410. Which Do You Need?

One of the most common questions we receive from new customers: 'What thread size do I need?' The thread labelling system may look cryptic at first glance, but it is actually logical and easy to understand. This guide will explain everything you need to know.

How to Read a Thread Designation

A thread designation consists of two numbers separated by a slash: for example 24/410. The first number (24) indicates the bottle neck diameter in millimetres. The second number (410) is the thread standard code, which defines the profile, pitch, and groove depth.

Most Common Threads in Cosmetics

• 18/410: the smallest standard thread. Used for serums, eye creams, and samples. Typically paired with 5-30 ml bottles.
• 20/410: popular for smaller cosmetic products in the 15-50 ml range. Common for essential oils and perfume samples.
• 24/410: the most widely used thread in cosmetics. Standard for 50-200 ml bottles. Most pumps and sprayers are available in this thread size.
• 28/410: larger bottles from 200 to 500 ml. Common for shampoos, shower gels, and lotions.
• 28/400: an older standard, still used for some household products. Note: it is NOT compatible with 28/410!

Threads for Household and Cleaning Products

For household products, in addition to cosmetic standards, you will encounter larger diameters: 28/410 is the most common for trigger sprayers on 500 ml-1 l bottles. For canisters and large formats, 38/400 and 45/400 threads are used.

Most Common Pairing Mistakes

• Confusing 400 and 410: they look similar, but the thread profile is different. A 28/410 closure on a 28/400 bottle will wobble.
• Ignoring neck height: the same thread can have different neck heights, which affects how the pump sits.
• Measuring the outer diameter: the thread is measured at the INNER diameter of the neck, not the outer.
• Assuming universality. 'a 24/410 pump' does not mean it fits EVERY 24/410 bottle. Always test with the specific bottle.

How to Proceed with Selection

• Start with the bottle: its thread determines which closure you need
• Verify the thread from the technical drawing or by measurement
• Order samples of both the closure AND the bottle and test the pairing
• For new projects, choose 24/410: it has a wide selection of closures
• When in doubt, send the bottle to your supplier: they will measure the thread for you

Not sure about the thread on your bottle? Send us a sample or a photo of the neck and we will recommend compatible closures from our range.