Mailing Envelope vs Bag: Which One Should You Use?

By Sam Smith

August 7th 2023

When it comes to sending documents and papers through mail or courier services, one of the most important decisions to make is whether to use a mailing envelope or a bag. Both options come with their own set of advantages and disadvantages, and it’s up to the sender to decide which one to choose based on their specific needs.

In this article, we’ll explore:

  • What are mailing envelopes and mailing bags?
  • Different types of mailing envelopes and bags
  • When to use either one
  • How to choose the best packaging for you

Mailing Envelopes

Mailing envelopes are a type of packaging material that is commonly used to send documents, letters, and small items through the mail. They have become an essential component of modern communication and commerce.

Whether you need to send a birthday card or a business letter, they offer a convenient and reliable way to get your message or package where it needs to go. These envelopes can come in different sizes, colours, and materials such as paper, cardboard, or plastic.

Here are a few things you should know about mailing envelopes:

  • They are lightweight and compact, making them easy and cost-effective to mail.
  • They are available in different types, including window, cushioned, and self-sealing envelopes.
  • Mailing envelopes are typically designed to be tamper-proof and tear-resistant, ensuring the contents are secure during transportation.
  • There are specific guidelines for using mailing envelopes, such as following size and weight restrictions and properly addressing them.

The UK follows the standards set by the ISO when it comes to envelope size. The Royal Mail deviates from this standard, but using an envelope no larger than C5 is a safe bet.

ISO Envelope Sizes and Dimensions

Envelope Size Dimensions (mm)
C0 917 x 1297
C1 648 x 917
C2 458 x 648
C3 324 x 458
C4 229 x 324
C5 162 x 229

Types of Mailing Envelopes

When it comes to sending mail, choosing the right envelope is crucial. There are several types of mailing envelopes that you can choose from depending on your specific needs. Let’s take a closer look at each of them:

Standard business envelopes

1. Standard Envelopes

Standard envelopes are the most commonly used envelopes for mailing letters, invoices, and other important documents. They are usually made from paper and come in different sizes, with the most common being the DL envelope. These envelopes typically have a rectangular shape and a gummed flap that can be sealed.

2. Window Envelopes

Window envelopes are similar to standard envelopes but have a transparent window on the front that allows the recipient’s address to show through. These envelopes are convenient for businesses that send a large volume of mail and can save time because you don’t have to manually write or print the address.

Padded Images

3. Padded Envelopes

Padded envelopes are a great option for sending fragile items such as jewelry, CDs, or DVDs. They are made of padded material on the inside to protect the contents and usually have a self-sealing flap.

Bubble Mailers

4. Bubble Mailers

Bubble mailers are another type of envelope for sending fragile or delicate items. They have a layer of bubble wrap inside that cushions the contents and protects them from damage. Bubble mailers come in different sizes and styles and can have anywhere from one to three layers of bubble wrap.

Choosing the right type of mailing envelope can help ensure that your mail is delivered safely and securely. Consider your contents, recipient, and postage requirements before selecting the best envelope for your needs.

When to Use Mailing Envelopes

Mailing envelopes are a great choice for many purposes. Here are some scenarios where you should consider using them:

1. Letters or Documents

Mailing envelopes are perfect for sending letters, documents, or other similar items. They come in various sizes, so you can choose the one that fits your needs. For instance, if you need to send a legal document, you can use a legal-sized mailing envelope to ensure that it fits perfectly and stays neat.

2. Lightweight Items

Mailing envelopes are also great for lightweight items such as photographs, books, and small items like jewelry or small clothing accessories. They offer a cost-effective way to send these items, as you can often send them through regular mail without having to spend extra on shipping.

3. Flat Items

If you’re sending flat items, such as artwork, certificates, or posters, mailing envelopes are the perfect choice. They are designed to be flat, which makes them ideal for these types of items. Plus, they offer protection during transit, ensuring that your item doesn’t get damaged.

Usage Benefits
Letters/docs Various sizes to fit needs
Flat items Cost-effective shipping


Mailing envelopes are perfect for letters, documents, and flat, lightweight items. They offer a cost-effective solution for shipping and provide protection during transit. With a mailing envelope, you can have peace of mind knowing that your item will arrive safely at its destination.

Mailing Bags

Mailing Bags: What Are They?

Mailing bags are large, flexible bags made of lightweight materials such as polyethylene or polypropylene. They are used for packaging and shipping various goods, documents, and envelopes that do not require extra padding or protection. Generally, mailing bags have a self-sealing strip that makes them easy to use and secure.

Mailing bags offer several useful benefits that make them popular for shipping various items. Here are some of the advantages of using mailing bags:

  • Lightweight: Mailing bags are lightweight, which makes them more cost-effective than traditional cardboard boxes for shipping purposes.
  • Durable: Despite their lightweight, mailing bags have good tear and puncture resistance.
  • Waterproof: Mailing bags are water-resistant, which keeps the items inside them safe from damage due to moisture during shipping.
  • Self-sealing: Almost all mailing bags have a peel-and-seal strip, which makes them easy to use, seal, and reopen if required.
  • Available in various sizes: Mailing bags are available in various sizes, from small courier bags to large Jumbo bags, making them suitable for various purposes.

Types of Mailing Bags

When it comes to mailing goods, envelopes aren’t always the best option. Sometimes you need something sturdier, more spacious and versatile. That’s where mailing bags come in. There are several types available, each with their own unique features and benefits. Let’s take a look at some of the most common ones:

Type of Mailing Bag Features
Polythene Mailing Bags Lightweight, waterproof, affordable, recyclable
Bubble Wrap Mailing Bags Cushioning, shock absorption, range of sizes
Tamper-Evident Mailing Bags Special seal, secure, great for valuable items and confidential documents
Gusseted Mailing Bags Expandable sides, extra depth, great for bulkier items
Paper Mailing Bags Eco-friendly, made from natural materials, strong

Polytheme Mailing Bag

Polythene Mailing Bags

Polythene mailing bags are the most popular option for ecommerce retailers. They are lightweight, waterproof and affordable. They come in a range of sizes and colors, making it easy to find one that suits your needs. They are also recyclable, making them an eco-friendly choice.

Paper Mailing Bag

Paper Mailing Bags

Paper mailing bags are an excellent choice for businesses who want to reduce their carbon footprint. Crafted from robust, single-ply kraft paper, they provide the same level of protection during transit as their counterparts. These bags are also biodegradable, offering a more sustainable solution for your business.

P.S. Our paper mailing bags have an expanding block bottom. You get the strength of a polythene mailing bags and the room of a gusseted in one.

Bubble wrap mailing bags

Bubble Wrap Mailing Bags

Bubble wrap mailing bags are a great choice if you need extra protection for your items during transit. They feature a layer of bubble wrap lining on the inside, providing cushioning and shock absorption. They come in a range of sizes and are perfect for fragile items like glass, electronics and ceramics.

Consider paper bubble wrap mailing bags if you want the same protection, but without the carbon footprint.

Tamper-Evident Mailing Bags

Tamper-evident mailing bags have become increasingly popular in recent years due to security concerns. They feature a special seal that shows if the bag has been opened or tampered with. They are great for sending valuable items and confidential documents.

Gusseted Mailing Bags

Gusseted mailing bags are perfect for sending bulkier items, such as clothing or soft toys. They feature expandable sides or a “gusset”, which give the bag extra depth and room for the items to move around. They are available in a range of sizes and colors.

When to Use Mailing Bags

While mailing bags have their benefits, it’s important to note that they’re not suitable for all items. If you’re shipping something valuable, fragile or that requires extra protection, always opt for a box or a padded envelope.

Here are some scenarios when using mailing bags might be the best choice:

Shipping non-fragile items

Mailing bags are not suitable for fragile items or those that require special handling. However, they are ideal for shipping items like books, documents, and small electronics that can withstand some movement or handling during transit. They’re perfect for shipping clothes, especially lightweight fabrics that don’t require extra padding.

Shipping flat items

Mailing bags are great for flat items that can be easily inserted into the bag and don’t require additional assembly or preparation. This makes them a perfect choice for shipping items like stickers, prints, and posters.

Saving on shipping costs

Mailing bags are typically lighter than boxes, which means they can save you money on shipping costs. They’re also easier to store and pack, which makes them a great option for small businesses or online sellers.

Mailing Envelope vs Mailing Bag: Which One to Choose?

When it comes to mailing items, whether for personal or business purposes, choosing the right packaging can make a big difference in ensuring your items arrive safely and intact. Here, we will look at the differences between mailing envelopes and mailing bags to help you decide which one is right for your needs.

Mailing Envelopes

Pros Cons
Lightweight Limited protection for fragile items
More affordable than mailing bags Not suitable for large or oddly-shaped items
Available in a variety of sizes and materials Still restricted on size by courier
Better protection than mailing bags Limited branding opportunities
Easy to store and transport in large quantities Limited security for sensitive documents

Mailing Bags

Pros Cons
Durable and resistant to damage Not suitable for fragile items
Suitable for larger or oddly-shaped items Limited protection
Various sizes and styles Not eco-friendly
Customisable Difficulty to stack
Lightweight Lack of cushioning
Easy to store and transport in large quantities Can be more expensive than mailing envelopes

How to choose between Mailing Envelopes and Bags

When planning to send mail or packages through the postal service or courier, it’s crucial to choose the right type of container to ensure that the contents arrive safely and undamaged.

We’ve put together a list of questions to help you decide:

What products are you sending?

When it comes to choosing between a mailing envelope and a bag, the content you’re shipping is your biggest factor. For those sleek documents, precious photos or other flat treasures, a snappy mailing envelope fits the bill perfectly. On the other hand, for your chunkier goodies like clothing, shoes, or soft items, a flexible and roomy mailing bag is your best bet.

Here’s a quick snapshot to help you decide based on the item you’re sending.

Mailing Bag Mailing Envelope
Clothing items (e.g., t-shirts, sweaters, socks) Letters, documents, or legal papers
Books or magazines Greeting cards or invitations
Small electronic devices (e.g., headphones, chargers) Brochures or pamphlets
Soft goods (e.g., pillows, blankets, towels) Photographs or prints
Sample products or promotional items Small flat items (e.g., stickers, patches, bookmarks)
Light-weight sports equipment (e.g., balls, bands) Thin or flat jewellery items (e.g., earrings, pendants)
Non-fragile cosmetics or beauty products Gift cards or vouchers

Are you shipping valuable items or sensitive documents? 

When it comes to sending valuable items like electronics, jewellery, or even cold hard cash, security becomes a top priority. The answer? Padded envelopes or secure bags equipped with tamper-evident seals, offering an extra layer of protection against the unwanted hands and potential damage during transit.

Is being eco-friendly at the heart of your business?

As the world is increasingly tilting towards environmental sustainability, your choice of packaging containers can make a huge difference. Mailing bags, often crafted from recycled plastic, offer a greener alternative to the conventional envelopes. These eco-friendly warriors are not just about saving the planet, they’re also about showing your customers that you care.

SmithPackaging sells both fully recyclable mailing bags and envelopes. With us, it doesn’t matter how you want to send your package, you’ll be doing your part for the world regardless.

Are you looking for cheapest or best value?

Who doesn’t love a good bargain? When it comes to the battle of costs between mailing envelopes and bags, envelopes typically come out on top. Particularly when buying in bulk, they’re usually a thriftier choice.

But hold on! Before you rush off to stockpile envelopes, let’s talk value. Mailing bags might cost a little more, but they often pack a punch in terms of bang for your buck. So, the question is, are you looking for the cheapest option or the one that offers the best value?

Wrapping Up the Great Mail Debate

In the grand scheme of things, choosing between mailing envelopes and mailing bags may seem inconsequential. However, as we’ve discussed, each option brings its own merits to the table. Whether it’s the cost-effectiveness of envelopes or the customisability of mailing bags, your choice will largely depend on the your products and your business’s specific needs.

Always remember: It’s not just about cost, but about delivering your products safely and professionally to your customers. After all, the satisfaction of your customers directly impacts your brand’s reputation and, ultimately, your bottom line.

So, envelopes or bags? There’s no definitive answer. But now, armed with the right knowledge, you’re empowered to make an informed decision. Keep your products, customers and business considerations in mind, and you’ll choose the packaging that best for your customers.

Delivered safe and secure.

9 million parcels were delivered damaged in 2022.

We can’t control the couriers drop-kicking your parcel over the back-gate – but we can offer the best padded packaging.

Your product will arrive safe and sound, with your customer eager to rip it open.

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