Custom Poly Mailers with Logo: The 2026 Guide to Branded Shipping

What Poly Mailers Are Good For

A poly mailer is a flat bag made of polyethylene film. It is light, thin, resists moisture and tearing, and takes up almost no storage space. The product goes in, the adhesive strip seals it, and the label goes on the outside.

These qualities make poly mailers a natural choice for e-commerce clothing and accessories, subscription items, documents and other goods that do not break. They also reduce shipping cost, because the package adds almost no weight or bulk.

Poly mailers are not a good choice for products that crush, scratch or snap. A mailer gives no structure, so a rigid or fragile item can be bent or broken by a stack of other parcels. For those, look at padded bubble mailers or a mailer box, which later sections compare.

If you ship clothing, our guide to the best packaging for mailing clothing compares more options.

Poly Mailer Sizes and a Size Chart

Poly mailers are described by width and length in inches. Stock sizes are widely used, and custom sizes are available. The chart shows common sizes drawn to the same scale, with what typically fits in each.

These are approximate. Garments fold differently and thickness varies, so test your own product. Also check whether the quoted length is the total length, which includes the flap, or the usable length inside the bag.

How to Choose Your Size

Follow these steps for each product you ship. It takes a few minutes with a ruler.

• Pack the product as you will ship it. Fold the garment, add the tissue, the card and anything else that goes in.
• Measure its width, length and thickness. Lay it flat and measure the width and length. Then measure how thick the pile is.
• Work out the width needed. A flat bag has to wrap around the thickness, so the mailer's width must be at least the product's width plus its thickness. Add about half an inch for ease.
• Work out the length needed. Add the product's length to the flap, which is typically about 1.5 to 2 inches, plus a little room.
• Round up to the next size. A slightly larger bag closes more easily and is gentler on the seal.
• Test with a sample. Pack, seal and shake it. If you have to force it, go up a size.

As an example, take a folded hoodie that measures 11 inches wide, 14 inches long and 2.5 inches thick. The width needed is about 11 + 2.5 = 13.5 inches, plus half an inch, so 14 inches. The length needed is 14 inches plus a 2 inch flap, plus a little room, so about 17 to 18 inches. A 14.5 x 19 inch mailer fits comfortably.

Do not go much larger than you need. A bag that is too big wastes film, flaps around, and can cost more to ship. A bag that is too tight strains the seal and splits. Our guide to measuring the dimensions of a box correctly covers the same habits for boxes.

Film Thickness (Mil) Explained

The thickness of the film is measured in mil. One mil is one thousandth of an inch, or about 0.025 mm. A higher number means a thicker, stronger film. It is the main reason one mailer feels flimsy and another feels sturdy.

These ranges are common in the trade, not a promise of what is available, and we confirm the film options with your quote. Mil is only one factor. The film blend, the opacity and the seal strip also affect how the mailer performs. If you ship something with hard corners, a zipper or a sharp edge, say so, and test a sample.

Opacity matters too. A thin white film can show the color and shape of a dark garment inside. Ask whether the film is opaque, which keeps products and customer details out of view.

Closures, Strips and Returns

Most poly mailers close with a self-sealing adhesive strip. You peel the liner off the flap and press it down, so you do not need tape. The strip is the most important part of the mailer, because it holds the parcel shut in transit.

• Single strip. The simplest and most common closure.
• Tamper-evident strip. A closure that shows if the parcel has been opened. Some mailers have one, so ask.
• Dual strips for returns. A resealable return mailer has a second strip, so the customer can seal it again and send an item back in the same bag.

If returns are a big part of your business, such as with fashion, a resealable style saves the customer from finding a new bag and saves you from paying for one. See our page on resealable return poly mailers. Print a short note near the second strip, such as "peel here to return", so customers know which one to use.

Ask how well the strip holds in the conditions you ship in, such as cold, heat or humidity, and how well the second strip holds after the first use.

Colors, Printing and Branding

A mailer is the first thing a customer sees, so printing your brand on it turns every parcel into a small billboard. Tell us the film color and the print colors you want, and we confirm the printing method, the number of colors and a proof with your quote.

Tips for Poly Mailer Artwork

• Keep a clear label zone. Leave a flat area, usually on the back, for the shipping label. A label over a busy pattern is harder to scan and read. Our guide to where to place a shipping label explains why.
• Keep print off the seal strip. Ink on the strip can interfere with the adhesive.
• Use bold shapes. Logos and simple repeating patterns work better than fine detail on a flexible film that creases.
• Think about contrast. Light colors on a dark film look weaker than the same colors on a light film. Ask for a proof.
• Plan for curves. The bag bulges around the product, so a design that depends on straight lines looks distorted.
• Check the film color. Typical options include white, black and solid colors, and we confirm what is possible.

Use CMYK for full-color artwork, or Pantone for an exact brand color. See color systems in packaging. Our free design support can help prepare artwork.

Types of Poly Mailers

Standard poly mailers are the baseline, and there are several variations for different needs.

Shipping Weight and Cost

A poly mailer adds almost no weight, and a packed mailer is flat, so it often ships for less than a box. Carriers charge by the larger of the actual weight and the dimensional weight, which is worked out from the package's size. Length x width x height, divided by a number called the divisor, gives the dimensional weight. The divisor depends on the carrier and the rate, so check the current one with your carrier.

As an example, take a hoodie that weighs 1.5 pounds. Packed in a box that measures 14 x 11 x 4 inches, the volume is 616 cubic inches. With a divisor of 139, the dimensional weight is about 4.4 pounds, so the carrier charges for 4.4 pounds. In a mailer that packs flat to about 14 x 11 x 2 inches, the volume is 308 cubic inches, which is about 2.2 pounds. These figures are illustrations, and carriers round each side up, apply their own rules and treat soft packages differently.

A mailer is only cheaper if it is the right size. An oversized or bulging mailer can lose the advantage. Our guide to the impact of packaging costs on product pricing explains how to count packaging, shipping and returns together.

Poly Mailer or Mailer Box?

A poly mailer is not always the right answer. The choice depends on the product, the brand and the journey.

Choose a poly mailer for soft goods where protection matters less than cost and size. Choose a mailer box for products that need structure, such as fragile items, gift sets or premium products where the unboxing counts. Choose a paper mailing bag or a padded envelope if you prefer a paper-based pack or need light cushioning. Some brands use a mailer box for the premium line and a poly mailer for basics. If you are unsure, our guide to choosing the right box for your product can help.

Recycling and Composting Claims

If the film material matters to you, ask us about the options and what we can document with your quote, because what the film is and what it is certified for decide what you can say on the pack.

A few general points help you decide. Standard polyethylene mailers are film plastic. Where they can be recycled depends on local programs, and many areas accept clean plastic film only through special drop-off collections, not through household recycling. Rules vary by town, so check locally. Compostable films are different materials, and composting works only where the right facilities exist. Home composting and industrial composting are separate standards.

In the US, environmental claims must be supported by evidence. Do not print "recyclable" or "compostable" on your mailer unless the film's documentation supports it for your market. Our guide to whether bubble mailers are recyclable and our overview of eco-friendly packaging materials go deeper.

You can also reduce waste with choices that do not depend on the material: right-size the mailer, avoid extra filler and consider whether a reusable return mailer would stop a second bag being used.

Ordering Custom Poly Mailers

Poly mailers start at 500 units. Send us the size, the film color, the thickness you want, the closure and your artwork, and say how many you ship in a month so we can suggest a quantity. Our quotes include shipping, and we reply within 1 business day.

Production takes 5 to 7 working days after artwork is approved and payment is received, with delivery time added on top. Larger or more complex orders can take longer, and we confirm the date in your quote. Free design support is available. If you are not sure about size or film, order a sample first. Our Samples page lists every sample type, and the Standard Sample Kit costs $50 with shipping included.

Common Poly Mailer Mistakes

• Choosing a size by guessing instead of measuring the packed product.
• Forgetting the flap in the length.
• Using a thin film for heavy items or items with hard corners.
• Printing over the seal strip.
• Leaving no flat area for the shipping label.
• Making light colors on a dark film and not asking for a proof.
• Using a poly mailer for fragile goods.
• Printing a recycling or composting claim without documentation.

Next Step

Measure your packed product, note its weight, and decide how you want the mailer to look. Then request a free quote and send your artwork if you have it. We will recommend a size and film.