Custom mailer boxes: sizing, materials and artwork explained

Mailer box or shipping box?

A mailer box folds from a single flat piece into a box with a hinged lid that tucks in at the front. It opens like a gift, which is why subscription brands and boutiques favor it. A standard shipping box has four top flaps closed with tape and is built for protection and stacking rather than presentation.

Choose a mailer box when the opening moment matters and the product is small to medium in size. Choose a shipping box when the contents are heavy, when boxes will stack in a warehouse, or when you ship a mailer box inside an outer carton for extra protection.

Many brands use both: a printed mailer as the presentation box, shipped inside a plain outer box when the item is fragile or valuable.

A quick way to decide is to ask who opens the box. If the end customer opens it at home and the product is the gift, a mailer earns its keep. If a retailer opens it in a stockroom and unpacks it onto shelves, nobody sees the print and a plain shipping carton is the better use of money.

Measure the inside, not the outside

Box sizes are normally quoted as inside dimensions in the order length × width × depth. Length and width describe the opening, depth is the height of the box when closed. Always confirm how a size is listed on the product page before ordering.

Measure the product in its finished state, wrapped in tissue or sitting in its insert, not bare. Then add clearance.

• For a single rigid item wrapped in tissue, add about 0.25 in to each dimension.
• For soft goods such as clothing, measure folded and add very little, since fabric compresses.
• For fragile items that need padding, add the thickness of the padding on every side.
• For several items packed together, arrange them the way you will pack them and measure the group.

Worked example: a candle measures 3.25 × 3.25 × 4 in. Wrapped in tissue with a card on top, it needs roughly 3.5 × 3.5 × 4.25 in inside. A 4 × 4 × 4.5 in box would leave room for a crinkle paper fill without rattling. A 6 × 6 × 6 in box would let it slide around and likely cost more to ship.

If you sell several products, resist the urge to create a box for each one. List every product with its packed dimensions, then look for two or three sizes that cover most orders with small inserts or fill to take up space. Fewer sizes mean larger runs per size, which lowers the unit price and simplifies storage. A product that fits none of your standard sizes can ship in a plain box with a sticker until its volume justifies its own print run.

Also consider how the box sits on a shelf or in a mail slot. A mailer that is just a little too tall for common letterbox openings will be left on the step or taken back to the depot, which hurts the experience you paid to create.

Board and flute basics

Corrugated board has a wavy middle layer called the flute, glued between flat liners. The flute size controls thickness, stiffness and how crisp the print looks. These are general descriptions, so check the product page for the exact board offered.

For most apparel, cosmetics, candles and accessories, E flute is the common choice because it folds cleanly and prints well. If the product is heavy or the box will travel without an outer carton, ask whether a sturdier board is available.

The outer liner also matters. White board shows bright colors accurately. Kraft board gives a natural brown base, so colors print darker and white ink may be needed for light designs.

Print coverage choices

The biggest cost decisions are how much of the box you print and on which side.

• Outside only, one or two colors: the most economical option and often enough.
• Outside full coverage: bold and memorable, but every scuff shows on dark flood colors.
• Inside print: a message or pattern revealed when the lid opens, strong for social sharing.
• Kraft with a single dark ink: a natural look that hides handling marks.

If budget allows only one upgrade, many brands choose a simple inside lid message over full outside coverage. The inside survives shipping untouched, while the outside meets conveyor belts and rain.

Think about the message as well as the decoration. The inside lid is a natural place for a short thank you, a hashtag or a line that sets up the product. The outside works best with very little: a logo, a web address and perhaps a tagline. Save longer copy for an insert card, which you can change every season without reprinting boxes.

If your products are sold as gifts, check whether printing the brand boldly on the outside is what customers want. Some shoppers prefer a discreet exterior so the recipient is surprised, and an inside print gives you branding without spoiling the gift.

Set up artwork on the dieline

A dieline is the flat template of the box showing every panel, fold and cut. Your artwork sits on this template, so it must be placed with the folded box in mind.

• Download the dieline for the exact size you are ordering and keep it on its own layer.
• Label each panel before designing: lid, front, back, sides, inside lid, base.
• Check orientation. Text on the front tuck often appears upside down on the flat layout because it folds over.
• Extend background color past cut lines by the bleed shown on the template.
• Keep logos and text away from fold lines, where board creasing can crack ink.
• Use vector logos and CMYK or specified spot colors, and convert fonts to outlines if the printer asks.

Before uploading, print the dieline at 100 percent on paper, cut it out and fold it. You will spot upside down text and misplaced logos in seconds. The artwork check and the guide to preparing artwork for print cover the file side in more detail.

Order a sample and test it with real contents

A box that looks perfect on screen can still fail in the mail. If a sample or short run is available, pack it exactly as a customer order and put it through a simple test.

Shake it. Nothing should rattle. Drop it from waist height onto each face and corner. Leave it overnight in a humid room. Then open it the way a customer would and note how the lid feels and how the product looks on first reveal. The sample scorecard gives you a consistent way to record these checks so you can compare sizes or boards fairly.

Check the color too. Hold the sample next to your business cards and website under daylight. Corrugated board absorbs ink differently from smooth paper, so a brand color can shift, especially on kraft. If the difference bothers you, adjust the artwork before the full run rather than hoping the production batch will look different.

Get the free Small Business Print Planner

The Small Business Print Planner includes a 12 month print calendar, a quote comparison sheet and an order checklist. Use the quote sheet to compare box sizes and boards on total cost per shipped order, not just price per box. It is waiting on the print planner page.

Mailer box ordering checklist

• Measure the product as packed and add clearance for wrapping and padding.
• Confirm dimensions are inside measurements in length × width × depth order.
• Choose board for the weight of the product and the shipping route.
• Decide on print coverage and whether inside print is worth it.
• Build artwork on the correct dieline with bleed and panels labeled.
• Fold a paper mockup before uploading the file.
• Test a sample with real contents before ordering a full run.