Custom Shirt Mailer Boxes That Post Flat

Sizing for a Folded Shirt

Fold a shirt exactly as you will ship it, with any tissue, collar insert or swing tag in place, and measure its length, width and height at the thickest point, usually the collar. Add a few millimetres to each dimension. That is your internal size. Dress shirts and casual shirts can often share a mailer; heavyweight flannels, overshirts and knitwear usually need a slightly deeper one.

Depth is worth getting right because it affects postage. A shallow mailer may fit a large letter or small parcel size band, saving money on every order. If the depth is close to a size limit, tell us your postage format and we will design the box to fit.

Folding method matters as much as the box. Shops that use a folding board get a consistent shape every time, which means one mailer size fits reliably. If several people pack orders, a simple folding guide pinned above the bench, with the target width and length, keeps every shirt within the box size you ordered and stops staff squeezing a loosely folded shirt into a box that was designed for a tighter fold. Our guide to measuring a product for a box covers folded garments.

• Measure the shirt folded, with tissue and inserts
• Add a few millimetres per dimension for fit
• Use a deeper mailer for flannel and overshirts
• Check the postal size band before fixing the depth

Board, Closures and Tear Strips

E-flute corrugated board is the standard for shirt mailers. It is thin, strong and prints well, and it bends neatly into the roll-end tuck-front style that most mailers use. White outer liners suit bright brand colours; kraft liners give a natural look and hide scuffs from the courier's van.

For extra security, a peel-and-seal strip on the closing flap keeps the box shut without tape, and a tear strip lets the customer open it in one pull. If you offer returns, a second peel-and-seal strip lets the customer reseal the same box and send it back, which saves them hunting for packaging and keeps the shirt protected on its way to you.

Printing Inside and Out

The outside of a mailer travels through depots and lands on doorsteps, so many brands keep it calm: a logo on the lid, perhaps a small pattern, and a clear space for the label. The inside is where the brand can be bolder. A full-colour pattern, a short welcome message or a care guide printed inside the lid creates a lovely moment when the box opens.

Printing inside costs a little extra but is often the most effective spend in an unboxing. Combine it with branded tissue paper, a thank-you card and a sticker sealing the tissue, and an ordinary shirt delivery becomes something customers photograph and share.

If your shirts are made to measure, consider printing a small panel inside the lid where the packer can write the customer's name or order reference by hand. It costs nothing extra once the panel is in the artwork, and it turns a standard mailer into something that feels made for one person. Inside print on brown and white board is compared in the print and finish options guide.

Packing Efficiently at Scale

When you ship many orders a day, small savings in packing time add up. Mailers that arrive flat, fold in one movement and close without tape are faster than boxes that need assembly and taping. Storing them flat saves warehouse space. Choosing one or two sizes that cover your whole shirt range keeps the packing bench simple.

If you also ship multiple shirts in one order, a deeper mailer that takes two or three folded shirts is useful. Ask us to quote both a single-shirt and a multi-shirt size together to see the difference.

Keep an eye on peak trading periods such as sales and launches, when order volumes jump. Holding a buffer of flat mailers in stock means a sudden rush does not leave the packing team reaching for plain boxes or poly bags. A sleeve that slides over a folded shirt for shop sales is covered under apparel sleeve boxes for shop shelves.

Agree the Fold Before You Agree the Box

A shirt mailer is only as consistent as the fold that goes in it. Before measuring, write down the fold your packers use, the board or tissue that goes inside and the collar insert if there is one, and fold three shirts that way; a dress shirt on a 380 x 270 mm board, a flannel without one. The thickest of the three sets the depth, and a 5 mm allowance on each side stops staff forcing a loosely folded shirt into a box drawn for a tighter one.

Send the folded shirt size, the quantity, the board colour, the print sides and the artwork, and a custom quote follows by email inside one working day, with mailers from £0.25 each and a low minimum worked out for the order. The free design proof shows the mailer flat with artwork on every panel. Production takes 4 to 7 working days after approval and free tracked delivery to UK mainland addresses arrives in 2 to 3 working days; misprinted or damaged mailers reported within 10 days are reprinted or refunded. Swimwear and lighter garments use the shallower swimwear boxes in the same board.