How to Select the Right Size Closures for Your Cosmetic Bottle

by | Jul 5, 2023 | Articles

As a cosmetic enthusiast and someone who understands the importance of packaging in the beauty industry, I know firsthand how crucial it is to select the right closures for cosmetic bottles. The right closure not only ensures the product’s integrity and longevity but also enhances the overall user experience. In this article, I will guide you through the process of selecting the perfect closure size for your cosmetic bottle, from understanding how closure sizes are defined to measuring bottle neck finishes accurately.

The world of closures can be overwhelming, with various sizes, finishes, and types available. It’s easy to get lost and end up with ill-fitting closures that compromise the quality and safety of your precious cosmetic products. By understanding the fundamentals of closure sizes and finishes, as well as learning how to measure your bottles and closures accurately, you can make informed decisions that will benefit both your brand and your customers.

Throughout this article, I will break down the essential aspects of closure selection, including common thread finishes and non-standard size closures. Whether you are a cosmetics brand owner, a packaging professional, or simply someone interested in the beauty industry, this guide will provide you with the knowledge and tools you need to confidently select the right closure size for your cosmetic bottle.

So, let’s dive in and explore the world of closures, starting with how closure sizes are defined. By the end of this article, you’ll be equipped with the expertise to ensure a perfect fit between your cosmetic bottles and their closures, creating a seamless and delightful experience for your customers.

How are closure sizes defined?

As we embark on the journey of selecting the right closure size for your cosmetic bottle, it’s essential to understand how closure sizes are defined. Closure sizes are standardized measurements that ensure compatibility between bottles and closures, allowing for a secure and functional seal. Let’s explore the key factors that define closure sizes:

1. Closure Size Standards:

Closure sizes are often defined based on industry standards, such as the DIN (Deutsches Institut für Normung) or GPI (Glass Packaging Institute) standards. These standards establish specific measurements and guidelines for closures, ensuring consistency across the industry.

2. Measurement Units:

Closure sizes are typically measured using two primary units: millimeters (mm) and inches (in). Millimeters are the most common unit of measurement, providing precise and accurate sizing. However, some closures, particularly those originating from the United States, might use inches as the unit of measurement.

3. Neck Finish:

When it comes to closure sizes, you’ll often come across labeling such as “18/410” or “24/415.” These numbers play a vital role in defining the appropriate closure size for your cosmetic bottle. Let’s break down the meaning behind these two numbers:

3.1. The first number:

The first number in the labeling, such as “18” or “24,” refers to the diameter of the closure. It represents the measurement in millimeters across the outside of the closure, including the thread. For example, an “18” closure would have an 18 mm diameter.

3.2. The second number:

The second number in the labeling, such as”400″,  “410” or “415,” indicates the bottle neck thread turn, that “400” stands for 1 thread turn, “”410″ stands for 1.5 thread turns,”415” stands for 2 thread turns. It refers to the standardized measurement of the bottle’s neck opening, which the closure is designed to fit. When you choose closures for your bottles, the number is critical important.

By understanding closure size standards, measurement units, and the importance of neck finishes, you can navigate the world of closures more effectively. When searching for closures, you will often come across labeling such as “18/410” or “24/415.” These numbers indicate the closure size and the corresponding neck finish. For example, “18/410” means the closure has an 18 mm diameter and is designed to fit a bottle with 1.5 thread turns.

Next, let’s explore common thread finishes to further enhance our understanding of closure sizes and their applications in the cosmetic industry. By familiarizing ourselves with these finishes, we can make more informed decisions when selecting closures for our cosmetic bottles.

Common Thread Finishes

In the world of closures, understanding common thread finishes is essential for selecting the right closure size for your cosmetic bottle. Thread finishes play a vital role in ensuring a secure and proper fit between the closure and the bottle’s neck. Let’s explore some of the most common thread finishes used in the cosmetic industry:

1. 18/415 Thread Finish:

The 18/415 thread finish is one of the most widely used in the cosmetic industry. It features an 18 mm closure diameter and a bottle neck finish with 2 thread turns. This thread finish is commonly found in small cosmetic bottles like sample vials, travel-sized containers or perfume bottles.

2. 20/410 Thread Finish:

The 20/410 thread finish is another popular choice for cosmetic bottles. It consists of a closure with a 20 mm diameter that fits a bottle neck finish and a bottle neck finish with 1.5 thread turns. Those bottles with this thread finish are commonly used in various cosmetic products, including lotions, creams, and shampoos.

3. 24/410 Thread Finish:

The 24/410 thread finish is often found in larger cosmetic bottles. It comprises a closure with a 24 mm diameter designed to fit a bottle neck finish with a 1.5 turns thread. This thread finish is commonly used in products such as body washes, serums, and moisturizers, essential oil.

4. 24/415 Thread Finish:

The 24/415 thread finish is often found in larger cosmetic bottles. It comprises a closure with a 24 mm diameter designed to fit a bottle neck finish with a 2 turns thread. This thread finish is commonly used in products such as body washes, serums, and moisturizers.

5. 28/410 Thread Finish:

The 28/410 thread finish is typically used for larger cosmetic bottles that require a wider opening. It features a closure with a 28 mm diameter that matches a bottle neck finish. This thread finish is commonly seen in products like shampoos, conditioners, liquid hand soap, and body lotions.

It’s important to note that these are just a few examples of common thread finishes. The cosmetic industry offers a wide range of sizes and variations to accommodate different bottle types and product viscosities. By familiarizing yourself with these standard thread finishes, you can easily identify the appropriate closure size for your cosmetic bottle based on the labeling or specifications provided by manufacturers.

In the next section, we will explore non-standard size closures, which offer more specialized options for unique bottle designs and specific product requirements.

Non-Standard Size Closures

While standard thread finishes cover a wide range of closure sizes, there are instances where non-standard size closures are needed. These closures cater to unique bottle designs, specialized packaging requirements, or innovative product formulations. Let’s delve into the world of non-standard size closures:

1. Customized Closures:

In some cases, cosmetic brands may opt for customized closures to align with their brand identity or create a distinct packaging experience. Custom closures can have unique shapes, sizes, or functionalities that set them apart from standard closures. These closures are often developed in collaboration with packaging manufacturers to ensure a precise fit with the corresponding bottle design.

2. Specialty Closures:

Specialty closures cater to specific product needs or usage requirements. For example, a product that requires controlled dispensing may utilize a closure with a built-in pump or dropper mechanism. These closures often have non-standard sizes to accommodate the additional features and functionalities they offer.

3. Airless Pump Closures:

Airless pump closures are designed to minimize product exposure to air, helping to preserve the quality and extend the shelf life of cosmetic formulations. These closures typically feature a vacuum-based dispensing system and come in various sizes to accommodate different bottle capacities and product volumes.

4. Unique Bottle Designs:

Bottles with unconventional shapes or sizes may require non-standard closures that are specifically designed to fit their unique dimensions. These closures are often developed alongside the bottle design to ensure a seamless and secure closure.

When considering non-standard size closures, it’s crucial to ensure compatibility with the bottle’s neck finish and the product’s intended usage. Working closely with packaging experts or manufacturers can help you identify and source the right non-standard size closures that meet your specific requirements.

Remember that while non-standard size closures offer flexibility and customization options, it’s important to balance aesthetics, functionality, and cost-effectiveness. Testing and prototyping are essential steps to ensure the compatibility, usability, and quality of non-standard size closures before implementing them in your cosmetic packaging.

Now that we understand the significance of non-standard size closures, let’s move on to the practical aspect of measuring bottles and closures accurately to ensure a perfect fit.


How do I measure a bottle and/or bottle closure accurately?

Accurate measurements are crucial when selecting the right closure size for your cosmetic bottle. By following a step-by-step process and using the appropriate tools, you can ensure precise measurements. Here’s a guide on how to measure a bottle and/or bottle closure accurately:

1. Measuring the Bottle Neck Finish:

  1. Ensure the bottle is empty and clean.
  2. Identify the outer edge of the bottle neck where the closure is applied.
  3. Use a caliper or ruler with millimeter measurements to measure the diameter of the bottle neck opening. Place the caliper or ruler across the widest part of the bottle neck and record the measurement.

2. Determining the Thread Finish:

  1. Examine the bottle neck finish for any visible threads or grooves.
  2. Count the number of threads on the bottle neck within a specified distance (e.g., 1 inch or 1 centimeter). This will help determine the thread finish, which is crucial for selecting the appropriate closure.

3. Measuring the Closure:

  1. For closures without threads (e.g., snap-on closures), measure the inside diameter of the closure using a caliper or ruler.
  2. For closures with threads, measure the outside diameter of the closure’s threads using a caliper or ruler.

4. Verifying the Compatibility:

  1. Compare the measurements of the bottle neck finish with the closure’s size specifications or labeling (e.g., “18/410” or “24/415”) to ensure compatibility.
  2. Consider the thread type (e.g., continuous thread or child-resistant) and closure style (e.g., screw-on, snap-on, or pump dispenser) to ensure a proper fit and functionality.

Remember, accuracy is key when measuring bottles and closures. Take multiple measurements and ensure consistent results. It’s also essential to refer to any industry standards or guidelines specific to your region or product requirements to ensure proper measurement techniques.

By following these measurement guidelines, you can confidently select the right closure size for your cosmetic bottle, ensuring a secure and functional seal that enhances the overall user experience.

In the next section, we’ll conclude our exploration of closure selection, summarizing the key points covered and emphasizing the importance of making informed decisions.

Additional Tips

In addition to understanding closure sizes, thread finishes, and accurate measurement techniques, here are some additional tips to consider when selecting closures for your cosmetic bottles:

1. Quality and Safety:

Prioritize quality and safety when choosing closures. Ensure that the closures you select comply with industry standards and regulations to maintain the integrity of your cosmetic products.

2. Consider Product Compatibility:

Different cosmetic products have varying viscosities and chemical compositions. Consider the specific requirements of your product when selecting closures to ensure compatibility and prevent leakage or product degradation.

3. Test and Sample:

Before committing to large-scale production, conduct testing and sampling with different closure sizes and styles. This allows you to assess the functionality and aesthetics of the closures and make any necessary adjustments.

4. Supplier Relationships:

Build strong relationships with reliable closure suppliers. Collaborate with them to discuss your specific needs, explore customization options, and stay updated on new closure innovations and trends.

5. Stay Informed:

The packaging industry is constantly evolving, with new closure sizes, designs, and materials being introduced. Stay informed about the latest developments and advancements to optimize your packaging solutions.

6. Branding and Aesthetics:

Consider the visual appeal of closures and how they align with your brand image. Customizable closures, such as ones with embossed logos or unique shapes, can enhance your brand’s identity and distinguish your products on the market.

7. Sustainability:

As sustainability becomes increasingly important, explore eco-friendly closure options. Look for closures made from recyclable materials or those that offer reduced environmental impact without compromising functionality.

By implementing these additional tips, you can refine your closure selection process and create a packaging solution that not only meets functional requirements but also aligns with your brand values and enhances the overall customer experience.

Remember, the right closure size is just one element of a successful packaging solution. Pay attention to every detail, from the closure’s functionality to its aesthetics and environmental impact. By doing so, you can create a cohesive and memorable packaging experience that resonates with your customers and sets your cosmetic products apart from the competition.

With a well-chosen closure, your cosmetic bottles will not only safeguard your products but also captivate consumers and leave a lasting impression. So, embrace the art of closure selection and elevate your packaging to new heights.


In conclusion, selecting the right closure size for your cosmetic bottle is a crucial aspect of packaging design and product integrity. By understanding how closure sizes are defined, familiarizing yourself with common thread finishes, and accurately measuring bottles and closures, you can make informed decisions that enhance the functionality and aesthetics of your cosmetic products.

Closure sizes are defined based on industry standards and labeling conventions, typically denoted by two numbers. The first number represents the closure diameter, while the second number indicates the bottle’s neck finish. Common thread finishes, such as 18/410 and 24/415, are widely used in the cosmetic industry and provide a standardized approach to closure selection.

However, there are also instances where non-standard size closures are required to meet specific design or product requirements. These non-standard closures offer customization options and specialized solutions, allowing for unique packaging designs and tailored product experiences.

Accurate measurement of bottle neck finishes and closures is essential for achieving a proper fit. By following a step-by-step measurement process and utilizing tools such as calipers or rulers, you can obtain precise measurements. Verifying compatibility between the bottle neck finish and closure size ensures a secure seal and optimal functionality.

In your journey of selecting the right closure size, remember to consult industry standards, guidelines, and manufacturer specifications specific to your region and product requirements. By doing so, you can confidently choose closures that not only protect and preserve your cosmetic products but also provide a delightful user experience for your customers.

As you venture into the world of closure selection, consider factors such as thread types, closure styles, and liner types to further optimize your packaging solutions. Additionally, explore eco-friendly closure options that align with sustainability goals.

With the knowledge and understanding gained from this article, you are now equipped to make informed decisions when it comes to selecting the right closure size for your cosmetic bottle. By paying attention to detail and prioritizing compatibility, you can ensure a seamless and secure packaging solution that enhances your brand’s reputation and customer satisfaction.

Remember, the right closure size is the final touch that brings your cosmetic bottle packaging to perfection. So, embrace the art of closure selection and create an unforgettable experience for your customers, one bottle at a time.


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