Mailer Box Sizes: Choosing the Right Dimensions for Shipping

For e-commerce, the mailer size is a cost decision as much as a fit decision – carriers price by size, so an oversized box wastes money on every order. This guide is part of our how to measure guide and pairs with our mailer boxes guide.

Common mailer sizes

Mailers cluster into rough tiers – small (around 6 x 4 x 2″) for accessories and beauty, medium (around 9 x 6 x 3″) for apparel and multi-item orders, and large (around 12 x 9 x 4″) for bigger or bundled products. These are starting points; the exact size should match your product.

How to pick the size

• Measure the product and add light clearance – see how to measure.
• Account for an insert if you are adding one – see inserts and unboxing.
• Keep it snug – a tight box means less void fill and lower dimensional weight.

Why size drives shipping cost

Carriers bill on dimensional weight, so a smaller mailer often ships cheaper even for the same product. Our dimensional weight guide explains how that math works.

Get the right mailer size

Tell us your product and we will size a mailer box to fit, with a free dieline. Start with our measuring guide, then request your free quote or contact our team.