There is no standard mirror box size, because a mirror box is not sized by the mirror. It is sized by the mirror plus the cushion you decide it needs, and the cushion is usually the larger of the two decisions. Work outward from the glass and the number falls out on its own.
Measure the mirror as it will be packed
Three numbers, taken on the finished piece rather than the spec sheet:
- Width and height at the widest point of the frame, including any moulding lip that sticks proud of the glass.
- Total depth, which is the part people get wrong. A wall mirror with D-rings, a hanging wire, a French cleat or rubber standoffs is thicker than the frame section. Measure across the hardware.
- Shipped weight, because glass is dense and weight, not size, is what picks the board grade.
What each protection layer adds to the box
Decide the protection first, then let it set the clearance. Every layer below adds its own thickness to the internal dimension.
| Layer | What it is for | Effect on the internal size |
|---|---|---|
| Corner protectors | The corner is where flat glass takes an impact and cracks. This is the highest-value layer. | Adds its own leg thickness to both width and height |
| Foam edge profile or U channel | Runs the full perimeter and stops edge chipping in transit vibration | Adds the channel depth to width and height, and its wall to depth |
| Bubble cushioning or foam sheet | Surface protection against scuffing on the reflective face | Adds sheet thickness to depth, usually twice if both faces are wrapped |
| Inner sleeve or telescoping second box | A suspended inner that never touches the outer wall | Adds the inner box board caliper plus the gap you leave between the two |
Board, and why mirrors end up double wall
Corrugated is specified by flute. E flute is about 1/16 inch and is a printing grade. C flute at about 3/16 inch is the ordinary shipping grade. Double wall stacks two flutes with a third liner, and that is where most framed mirrors land once the shipped weight is real. Rather than choose off a chart, send us two numbers: the weight of one packed box, and how high those boxes stack on a pallet. Board grade is a response to load and stack height.
Stating the dimension so nobody guesses
Write it as internal length x width x depth, in that order, and label it internal. On a double wall box the difference between internal and external is not trivial, and a mirror that fits the internal number will not fit the same figure read as external. Ask for the confirmation in writing on the quote. The die is included, so an internal size that matches your exact frame costs no more to tool than a rounded one.
Ordering
Minimum order is 100 boxes. Pricing starts from about $0.48 per unit at bulk volumes, confirmed on your written quote. The die, the plates, design support, US shipping and a digital proof before anything prints are all included. We make in two plants, West Chicago in the US and Guangzhou in China, and turnaround is quoted per product in three lanes: rush (expedited production plus air freight), standard (air) and cost saver (sea), from about 7 business days plus 2 to 5 for delivery. Specialty imported constructions can run up to about 12 weeks.
If the mirror needs a fitted cavity rather than loose fill, look at boxes with foam inserts, where the foam is cut to the frame and the box is sized around it. If it is going to ship as part of a mixed pallet, the method on sizing a corrugated shipping box covers the outer.
Send the three measurements and the protection you have in mind through the quote form and we will come back with the internal dimension, the board and a written price. If you are not sure the cushion is enough, say what you are shipping and we will say what we would specify.
