E-commerce shops predominantly use mailers bags to ship their products since they are lightweight and reusable. This often translates to cheaper shipping costs. This guide will share with you tips on choosing the right mailer bag size and maximizing the mailer space so you and your customers save on shipping costs.

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What are the standard sizes of Mailer Bags 

These bags come in a wide variety of sizes, which can make finding the correct bag size difficult. Across shopping and shipping platforms, the standard size for poly mailers is usually 10" x 13". However, other sizes such as 6" x 12" and 14.5" x 19" are available for smaller and bigger products.

What Size Mailer Bag Should I Buy?

Here are four (4) things to keep in mind when determining the size of mailer bags you should buy:

1. Size of the Product

While it may seem cliché, you should consider this an essential aspect of choosing your packaging. The size of the product will dictate the size and type of the mailer bag you will use.

However, not all products will fit just any mailer bag size. You should accurately measure the item to determine the mailer size. This will make sure the size you'll end up buying is the one closest to what you need.

Regular shaped items are the easiest to measure. Using a ruler or tape measure, measure the length (longest side), width (shorter side), and depth (thickness) of the product.

When it comes to cylindrical and irregularly shaped objects, measure them rectangularly. For clothes and fabrics, you should fold them rather than roll them. You can check our Eco-friendly Packaging Tips for Clothes guide for quick and efficient folding tips.

 Check out this amazing packaging video from @colemanscrafts

2. Size of the Mailer

Ideally, the mailer should be larger to completely wrap the product while leaving enough room to seal the bag properly. If you use an undersized mailer bag, your packaging will likely tear and rip during handling or transit.

Note: An oversized mailer will increase your shipping costs due to its dimensional weight.

We have developed a simple formula to help you determine the minimum length and width sizes of mailer bags:

Mailer size = (L + H + 2") x (W + H + 1/2”) Where:

• L – Product length
• W – Product width
• H – Product height/depth

The formula will provide a rough estimate of the L × W of the mailer you need. You can use our size calculator for simple, quick, and accurate readings. The calculator's advantage is gauging how much space you can pack inside a biodegradable mailer. Multiply all the dimensions of your mailer (L × W × H) to get the volume in square inches.

 Check out our mailer bag size calculator 

Alternatively, you can use the dimensional calculators from major shipping labels such as USPS, UPS, and FedEx. Apart from the mailer size, these calculators correctly determine the billable weight by factoring in the total number of products and their dimensional weight.

3. Cushioning

Delicate and valuable items such as jewelry require some cushioning to withstand the rigors of shipping.

When determining the size of a mailer, it's essential to know that the cushioning will significantly reduce the internal dimensions of the mailer. For instance, 4-6 medium shirts will easily fit into a 10" x 13" flat mailer, but only about 3-4 will fit into a padded mailer. Consequently, adjust the size of your mailer bag accordingly based on the type of padding you will use.

If a small, fragile item requires cushioning, we recommend that you use a bubble mailer. While the bubble mailers pack fewer items than flat mailers, they are convenient and eco-friendly way of protecting small and delicate products. They help to reduce packaging waste, which helps in making your shipping method more sustainable and environment-friendly.

 Check out this cool jewelry packaging video from @delroseco

Use the bubble mailer calculator to select check if your small, fragile items can fit into these protective bags.

4. Shipping Specifications

Shipping companies have specific size and weight guidelines prescribed in their manuals. Remember to adhere to these guidelines strictly, since the couriers usually verify all packages before shipping them out.

Discrepancies between dimensions specified, and your actual dimensions, will often need to be reviewed. It is a time-consuming process and these checks usually leads to delays in the delivery of the products.

In case, your product's dimensions go beyond what is recommended, the weight class will have to be increased. This often results in increased shipping costs. Also, in some extreme cases, the package might be returned, which increases the likelihood of delays.

What Items Can You Fit Into Poly Mailer Bags

Poly mailer bags are an ideal replacement for shipping boxes when packaging small, light items. Use a bubble mailer or paper wrap if the items are fragile and need extra protection. You can also use poly mailers to ship health and beauty products, provided they are in sturdy, rip-proof materials.

Let’s look at some of the products you can fit into the different sizes of a poly mailer. Remember, the quantity of the items you can fit in may vary depending on the product's thickness, material or other things that may affect its volume.

For 6 × 9” Mailer Bags

Here are the items you can possibly fit into 6 × 9” mailer bags:

• Baby Socks
• Small Art Prints
• Health supplements
• Small jewelry box
• cases
• Deck of Cards
• Small Cosmetic Items

What products can fit into a 6×9” mailer bag

For 10×13” Polymailer Bags

What could you fit inside a 10 × 13” polymailer?

• 2-3 neatly folded t-shirts
• Children Sneakers
• A pair of jeans
• Books and magazines
• Toys (boxed)
• A yard of fabric
• Board games

What can you pack in a 10 × 13” polymailer

For 14.5 × 19” bag

• Beddings – a blanker or set of sheets
• A hoods or jackets
• Adult shoebox
• 2-3 yards of fabric
• Art prints

What can fit in 14.5 × 19” mailer bags

Maximize the Packaging Space

Maximizing the space of your mailer ensures that your shipping costs stay within your budget. For maximum efficiency, pick the most suitable type of mailer, depending on the size and shape of your item. Or you can mount promos that encourage multiple purchases or orders.

Use flat mailers to ship light and less-fragile items such as clothing, bedding, fabrics, and print materials. Bubble mailers are ideal for delicate items such as crafts, jewelry, and small electronics.

It's crucial to accurately determine the dimensions of your product. Calculating the size of mailer bags is now easier with the availability of mailer bag size calculators. 

A Guide to Poly Mailer Sizes: Find the Perfect Fit for Your Products

Jump Right In: A Guide to Poly Mailer Sizes

What Are Poly Mailers?

When it comes to shipping, the packaging you choose can make all the difference. This is where poly mailers come in, a popular choice for e-commerce businesses and shippers worldwide. But what exactly are poly mailers?

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Poly mailers are lightweight, protective mail envelopes made from polyethylene film. Polyethylene is a type of plastic—specifically, a thermoplastic polymer that makes these mailers incredibly durable and flexible. They are designed to protect goods from moisture, dust, and minor bumps during transit, with a self-sealing adhesive strip that ensures contents stay securely inside.

Here’s why so many e-commerce sellers opt for poly mailers:

• Lightweight: Poly mailers are thin and weigh very little on their own, which helps keep shipping costs down. Lightweight packaging materials like polypropylene are not only cost-effective but also reduce the overall weight and volume, leading to lower transportation costs​ (Diamond Box)​.
• Waterproof and Tear-Resistant: These mailers resist water, making them ideal for shipping in various weather conditions. They are also difficult to tear, which helps keep your products safe from external damage and tampering.
• Flexible: Unlike rigid boxes, poly mailers can conform to the shape of your product, which reduces bulk and the space required for shipping. This flexibility makes them perfect for apparel, fabrics, and other non-fragile items.

In e-commerce, poly mailers are typically used to ship:

• Clothing and textiles, as these items do not require the structural support of a box.
• Small accessories like belts, scarves, and fashion jewelry.
• Non-fragile beauty products and supplements.
• Any items that need a basic level of protection from environmental factors but are not susceptible to damage from mild pressure or bending.

Poly mailers are a straightforward, cost-effective solution for shipping goods that do not need the high level of protection a box might offer. They are especially valued for their practicality and the efficiency they bring to the packing and shipping process—qualities every e-commerce business can appreciate. Whether you’re a seasoned online seller or just starting, incorporating poly mailers into your shipping solutions can lead to significant savings and improved customer satisfaction due to the pristine condition in which your products arrive.

Understanding Poly Mailer Sizes

Selecting the right size poly mailer is crucial to shipping efficiency and minimizing costs. With a variety of sizes available, knowing which one to use can make a big difference. Here’s a guide to understanding the standard sizes of poly mailers available in the market and how to choose the right one for your products.

Poly mailers come in a range of sizes to accommodate everything from a set of earrings to a bundled-up hoodie. The industry typically offers these sizes in a standardized range, similar to envelopes, which can be selected based on the dimensions of the product being shipped. Here’s a closer look at how these sizes are generally categorized:

• Small (6 x 9 inches to 9 x 12 inches): Best for small items like jewelry, books, or electronics.
• Medium (10 x 13 inches to 12 x 15.5 inches): Ideal for shirts, blouses, and documents that do not require folding into smaller dimensions.
• Large (14 x 17 inches to 19 x 24 inches): Suitable for larger clothing items, multiple pieces of apparel, or thick documents.
• Extra Large (20 x 24 inches to 24 x 36 inches): Used for bulky items like coats, large numbers of clothing, or linens.

Determining the Right Size: Usable Space vs. External Dimensions

When choosing a poly mailer, it’s important to understand the difference between usable space and external dimensions. The usable space refers to the interior area available for your product, which is slightly less than the external dimensions because of the material thickness and the space taken by the seal flap. Always measure your item and ensure it fits within the usable space, not just the overall external dimensions.

Size CategoryExternal Dimensions (inches)Usable Space (inches)Suggested Uses Small6 x 95.75 x 9Jewelry, small electronics 9 x 128.75 x 12Books, documents, accessories Medium10 x 139.75 x 13T-shirts, lightweight tops 12 x 15.511.75 x 15.5Multiple apparel items Large14 x .75 x 17Pants, dresses, thicker garments 19 x .75 x 24Multiple clothing items, large docs Extra Large20 x .75 x 24Coats, blankets, bulky items 24 x .75 x 36Large linens, pillows

Tips for Selecting the Correct Size

• Avoid Oversizing: Using a mailer that’s too large can lead to your product moving around during shipping, which could increase the risk of damage.
• Leave Space for Closure: Ensure there’s enough room to seal the mailer without pressing against the item inside.
• Consider Multiples: If you often ship multiple items together, consider a size that accommodates the combined dimensions.

Choosing the right poly mailer size not only protects your items during transit but also optimizes your shipping costs by avoiding excess packaging. With this guide, you can select the perfect size for your products, ensuring they arrive safely and cost-effectively to your customers.

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How to Choose the Right Poly Mailer Size

Choosing the correct poly mailer size is more than just a matter of picking a bag that fits. It involves understanding the dimensions of your product, the mailer’s capacity, and ensuring there is a balance between protection and cost-efficiency. Follow this step-by-step guide to measure your products accurately and select the ideal poly mailer size.

Step-by-Step Guide to Measuring Products for a Poly Mailer

1. Measure Your Product: Start by measuring the length, width, and height of your product. If it’s a soft item like clothing, lay it flat to measure it in its smallest form.
2. Determine Thickness: For bulkier items, consider their thickness after being folded or rolled. This affects the choice of mailer size significantly.
3. Allow for Extra Space: It’s essential to add a little extra to each dimension to facilitate easy insertion and removal. A good rule of thumb is to add half an inch to each dimension.
4. Match to Mailer Dimensions: Use the dimensions obtained to select a poly mailer that is slightly larger. Refer back to the size chart provided in the previous section to identify the best fit.

Want more insights?

Check out this great video by Shipping Things that gives tips on choosing the right Poly Mailer Size for your products!

The Importance of Correct Sizing and Understanding DIM Weight

Selecting the right poly mailer size is crucial for ensuring that your products arrive safely and cost-effectively. By carefully measuring your items and considering the key points below, you can avoid common pitfalls and optimize your shipping processes. Remember, the goal is to protect your product while maintaining an efficient, cost-effective delivery system.

Prevent Damage: An undersized mailer may tear or burst during transit, exposing your product to potential damage and loss. Conversely, an oversized mailer has excess material that can snag, tear, or allow the product to move too much, which also increases the risk of damage.

Cost Efficiency: Using the smallest possible mailer for your product not only reduces material costs but also lowers shipping costs, as carriers often charge based on size and weight. Correct sizing ensures you aren’t paying for the additional weight of an unnecessarily large mailer. Furthermore, understanding dimensional weight (DIM weight) is essential. Shipping carriers calculate DIM weight by multiplying the length, width, and height of a package and dividing by a standard DIM divisor. This method helps determine the shipping cost based on volume rather than just weight. Selecting an appropriately sized poly mailer minimizes the DIM weight, potentially reducing shipping costs further.

Professional Presentation: The right-sized mailer makes a positive impression on customers. It shows that you are considerate about your product’s presentation and committed to sustainable practices by minimizing waste.

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The Importance of Correct Poly Mailer Sizing

• Prevent Damage: An undersized mailer may tear or burst during transit, exposing your product to potential damage and loss. Conversely, an oversized mailer has excess material that can snag, tear, or allow the product to move too much, which also increases the risk of damage.
• Cost Efficiency: Using the smallest possible mailer for your product not only reduces material costs but also lowers shipping costs, as carriers often charge based on size and weight. Correct sizing ensures you aren’t paying for the additional weight of an unnecessarily large mailer.
• Professional Presentation: The right-sized mailer makes a positive impression on customers. It shows that you are considerate about your product’s presentation and committed to sustainable shipping practices by minimizing waste.

Selecting the right poly mailer size is crucial for ensuring that your products arrive safely and cost-effectively. By carefully measuring your items and considering these key points, you can avoid common pitfalls and optimize your shipping processes. Remember, the goal is to protect your product while maintaining an efficient, cost-effective delivery system.

When to Use Poly Mailers

Poly mailers are a versatile shipping option, ideal for a wide range of products. Knowing when to use them can help you streamline operations, reduce costs, and ensure customer satisfaction. Here’s a look at the ideal products for poly mailers and the benefits they offer over other packaging solutions.

Ideal Products for Poly Mailers

Poly mailers are best suited for non-fragile items that are relatively flat and not prone to damage from pressure or bending. Some of the best candidates for poly mailers include:

• Clothing and Apparel: Most types of clothing, such as t-shirts, jeans, dresses, and jackets, can be easily folded and fit within poly mailers, making them a popular choice for fashion e-commerce businesses.
• Textiles: Items like bed sheets, pillowcases, towels, and tablecloths are ideal for poly mailers because they are soft and can be compressed without damage.
• Accessories: Scarves, gloves, and even some shoes (like flip-flops or flats) can be shipped in poly mailers, as they don’t require rigid protection during transit.
• Soft Goods: Soft toys, crafts, and other non-breakable items are also suitable for poly mailers.

Benefits of Using Poly Mailers

Choosing poly mailers over boxes or other types of packaging can offer several advantages:

• Cost-Effective: Poly mailers are generally cheaper than boxes. They’re lightweight, which helps keep shipping costs down, as most carriers charge based on weight.
• Space Efficiency: They take up less space in storage and in transit, allowing shippers to load more packages onto a truck or plane. This can lead to cost savings, particularly for high-volume shippers.
• Durability: Made from water-resistant and tear-resistant material, poly mailers protect goods from environmental factors like moisture and dirt, which can be especially useful during adverse weather conditions.
• Reduced Waste: Poly mailers use less material than boxes, which contributes to waste reduction. They are also increasingly available in recyclable and biodegradable forms, appealing to environmentally conscious businesses and consumers.
• Ease of Use: They come with self-sealing closures, eliminating the need for additional packing tape and making the packaging process quicker and easier.

Comparison with Other Packaging Options

While poly mailers are an excellent choice for many scenarios, they are not suitable for all. For instance, fragile items, electronics, and bulky goods that can be damaged by compression or sharp impacts are better suited to rigid packaging like corrugated boxes. Boxes provide better protection for such items by resisting punctures and cushioning impacts.

For businesses shipping non-fragile, flat, or soft items, poly mailers offer a cost-effective, durable, and efficient packaging solution that is both easy to handle and reduces shipping costs. Choosing the right packaging not only protects your products but also enhances the unboxing experience, reflecting on the overall brand perception.

When Not to Use Poly Mailers

While poly mailers are an excellent choice for many shipping needs, they are not universally suitable for all types of products. Understanding when not to use poly mailers can help prevent product damage, customer dissatisfaction, and potential returns. Here are some scenarios where poly mailers may not be the best choice, along with alternatives that can offer better protection.

Scenarios Where Poly Mailers Are Inadvisable

1. Fragile Items: Shipping fragile items that can break, such as glassware, ceramics, and certain electronics, need more protection than poly mailers can provide. These items require rigid packaging to cushion and shield them from shocks and impacts during transit.
2. Very Bulky or Rigid Items: Large or awkwardly shaped items that do not conform easily to flexible packaging could tear or stretch a poly mailer. Items like large toys, home decor, or boxed products are better suited to sturdier packaging options.
3. High-Value Items: Products that have a high monetary or sentimental value might require enhanced security features and additional protective measures that poly mailers cannot offer.

See how DIM Weight affects your shipping costs.

Check out the comprehensive guide how to determine your product’s DIM weight and how you can reduce it to save on shipping.

Alternatives to Poly Mailers

When poly mailers are not suitable, consider these alternatives:

• Corrugated Boxes: The go-to choice for most fragile and bulky items, corrugated boxes come in various strengths and sizes, providing excellent protection against crushing and dropping. They are also better at accommodating cushioning materials like bubble wrap or packing peanuts.
• Padded Envelopes: For smaller, fragile items, padded envelopes offer an additional layer of protection with built-in bubble wrap or foam padding. They are more flexible than boxes but provide more cushioning than standard poly mailers.
• Rigid Mailers: Ideal for flat items that need a bit more protection than a poly mailer can offer, such as photographs, documents, or CDs. Rigid mailers are made from stiff cardboard and help prevent bending and corner damage.

Using Protective Packaging Materials with Poly Mailers

In cases where you opt to use poly mailers for items that are somewhat fragile, or if you want to ensure extra protection, consider the following tips:

• Bubble Wrap: Encase your product in bubble wrap, which provides air-cushioned protection against impacts. Ensure that the bubble wrap covers all sides and corners of the product.
• Foam Inserts: Custom-shaped foam can secure the product within the poly mailer and absorb shocks effectively.
• Corrugated Inserts: Adding a piece of corrugated cardboard inside the poly mailer can offer added rigidity and protection against bending and puncturing.
• Sealed Air Bags: These can fill up excess space inside the mailer, preventing the product from moving around during shipping, which is often a cause of damage.

While poly mailers are an effective and cost-efficient shipping solution for many e-commerce businesses, they are not a one-size-fits-all solution. Assessing the nature and needs of the product you’re shipping is crucial to choosing the most appropriate packaging option, ensuring your items arrive in excellent condition and keeping your customers happy.

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Summary

Selecting the correct poly mailer size is not just a detail in the process of shipping—it’s a fundamental aspect that can significantly influence the cost-effectiveness, efficiency, and customer satisfaction of your e-commerce business. Throughout this blog, we’ve explored the various sizes of poly mailers available, how to choose the right one for your products, and the ideal scenarios for their use. We also discussed when it might be better to opt for alternative packaging options to ensure that every product arrives in pristine condition.

Experimentation is key in the world of e-commerce. Don’t hesitate to try different poly mailer sizes and types to discover the perfect fit for your diverse product range. Sometimes, the best way to determine the most effective packaging is through trial and reflection on real shipping experiences.

We invite you to share your experiences and tips in the comments section below. Your insights could help other e-commerce sellers optimize their packaging strategies. What worked for you? What didn’t? Let’s learn from each other and continue to improve our shipping practices together.

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