Envelope Mailers
Durable, Branded, and Built for Simplicity
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Mailer
What Are Envelope Mailers?
Rigid Paperboard Mailers for Documents and Flat Products
Envelope mailers are flat, self-sealing packages designed to ship documents, inserts, promo materials or lightweight products. Think of them as the premium, branded version of a FedEx-style overnight mailer but made from recyclable, high-caliper paperboard with full-color printing.
When Simplicity and Strength Are Key
Not as common as folding cartons or shipping boxes, envelope mailers are a practical solution for brands that need slim, protective packaging for items that can’t bend or crease in transit.
When your product needs to make a quick exit.
Features of Our Envelope Mailers
Made from Heavy-Duty Paperboard
We use thick, rigid paperboard (24pt or 28pt) to create mailers that can protect your contents during shipping without requiring additional void fill or corrugated boxes.
Peel-and-Seal Closure
Each mailer has a double-sided adhesive strip for quick, secure closure. Some options have a second strip for easy customer returns.
Custom Sizes and Layouts
Whether you’re mailing flat prints, promo kits or lightweight products like sticker packs, pins or documents, we can size the envelope to your exact specs.
Professional Branding
Unlike stock mailers, these can be fully printed with your branding, logo, campaign graphics or messaging. You can also choose from matte, gloss or soft-touch coatings.
Curious what overnight envelopes cost?
Get a quick quote below — all you need is your box dimensions.
And if you’re not sure where to measure, we’ll walk you through it.
Click here for an instant quote
And find out about...
✔️Easy Way to Measure
✔️ Paper Thicknesses
✔️ Types of Print Finishes
Style of box
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Have questions? Talk to a real human.
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Chat with us - Use the chat bubble at the bottom right
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Call us (800) 555-1778
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Email us - quotes@boxcoop.com
Get a Quote in 3 Simple Steps
✔️ Choose Your Box Style
✔️ Enter Your Dimensions
✔️ Get Instant Quote
Style
Size:
Length
Width
Depth
Height
Options:
UV
Hang Tab
Window
Volume
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18pt total costs
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18pt cost/box
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24pt total costs
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24pt cost/box
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How Did We Come Up With These Costs?
Our Custom Product Box Costs Explained shows exactly what goes into your quote—and how to make the most of your product packaging budget.
Help →
Paper Thickness
Print Finishes
Measure
Reading a Ruler
Paperboard Thickness Chart
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What's a Good Paper Thickness for My Box?
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16pt (0.016″ ≈ slightly thicker than a business card)
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Best for very small product boxes.
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Rule of thumb: footprint (floor of the box) of about 1″ × 1″ or smaller.
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18pt (0.018″ ≈ just under credit-card thickness)
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Strong enough for most cosmetics, food, and shelf packaging.
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Cost-effective and versatile — the “everyday” choice for custom boxes.
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Rule of thumb: footprint of about 2.75″ × 2.75″ or smaller.
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24pt (0.024″ ≈ credit-card thickness)
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Stiffer and more rigid, with a premium feel in hand.
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Ideal for larger, heavier, or higher-end products where strength and presentation matter.
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Rule of thumb: footprint of about 3″ × 3″ or larger.
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Cardstock.... or Paperboard?
The paper behind your packaging matters
You may have seen box specs like “18pt cardstock” online — but not all 18pt paper is created equal.
• Cardstock: A thick paper used for crafts, postcards, and invitations. It’s cheaper and technically works for light packaging — but it lacks the stiffness and durability needed for most product boxes.
• Paperboard: A stiffer material engineered specifically for packaging. It folds cleanly, glues reliably, and holds its shape to protect your product — and your brand — on the shelf.
The key is knowing what you’re buying. In retail, your product box is what closes the sale — so it needs to perform and look its best. That’s why we use a quality paperboard — so your packaging doesn’t just hold together, it helps sell what’s inside.
Ideal Use Cases for Envelope Mailers
Marketing Collateral: Flat brochures, catalogs, samples, press kits
E-Commerce Inserts: Subscription inserts, postcards, loyalty gifts
Event Materials: Trade show kits, product launch invites, branded documents
Retail Merchandise: Flat accessories, pins, stickers or small apparel
Benefits of Paperboard Envelope Mailers
Lightweight and Low-Profile
Envelope mailers minimize shipping weight and reduce dimensional pricing, saving you money on direct-mail campaigns or sample shipments.
Sturdy Without the Bulk
Our rigid mailers offer more protection than a poly mailer or paper envelope, without the bulk of a box. Perfect for flat or thin contents that need to arrive crisp and undamaged.
Eco-Friendly and Recyclable Made from recyclable paperboard and printed with soy-based inks, our envelope mailers support your brand’s sustainability goals.
Fully Customizable
Edge-to-edge artwork to interior printing, foil stamping or embossed logos, we can make your mailers look as sharp as they function.
Envelope Mailer FAQs
What Are Envelope Mailers Made Of?
Our envelope mailers are made from high-caliper coated paperboard, 20pt-28pt depending on the required rigidity.
Can These Mailers Be Printed Inside and Out?
Yes! We offer full coverage print inside and outside for a branded experience from opening to finish.
Are Envelope Mailers Recyclable?
Yes. All paperboard mailers we produce are 100% recyclable and made from sustainably sourced materials.
What Are the Minimums for Custom Envelope Mailers?
Typical minimums start at 500 units but we may accommodate smaller runs depending on the size and finish.
Good for Fragile Items?
Best for flat, semi-rigid items. For fragile or dimensional products we recommend pairing with inserts or our folding carton or litho-lam options.
Get Started on Your Custom Envelope Mailer Project
Tell us what you need to ship or promote and we’ll help you design a rigid paperboard envelope mailer to fit your brand and protect your content.
Work with Experts in Premium Paperboard Packaging
At The Box Co-op we focus exclusively on paperboard packaging from custom boxes to branded mailers. If you need a clean, professional way to deliver flat products our envelope mailers are built to impress.