Round Flat Items in Mailers: Diameter and Clearance
For a round item packed flat, the mailer's shorter inside side limits the diameter. Extra space along its longer side and in the corners cannot compensate for a diameter that is too large. Measure the round item with its edge protection already in place.
This guide addresses discs, round signs and other flat circular objects that remain flat in the package. It does not assume a particular material, weight or protective requirement.
Compare protected diameter with both inside sides
MFL22182 literature mailers have listed inside dimensions of 22 × 18 × 2.75 inches. Their 18-inch side is the tighter diameter constraint for a circular assembly laid flat. Rotating a circle within that plane does not change its diameter.
A hypothetical 19-inch circular assembly has an area of about 283.5 square inches. The mailer's rectangular floor has a nominal area of 22 × 18 = 396 square inches. The circle has less area, but its diameter still exceeds the 18-inch inside side. Floor area alone gives the wrong fit answer.
| Protected diameter | Packed height | Screen against 22 × 18 × 2.75 inches |
|---|---|---|
| 19 in | 2 in | Diameter exceeds the shorter inside side |
| 17 in | 3 in | Footprint fits nominally, but packed height exceeds 2.75 inches |
| 17 in | 2.5 in | Within all three listed dimensions; proceed to a sample |
Do not count the corners as an even protective border
Center the hypothetical 17-inch assembly in the nominal 22 × 18 inch footprint. The diameter leaves 5 inches in total along the longer axis and 1 inch along the shorter axis. Centering divides those amounts into 2.5 inches at each long-axis end and 0.5 inch at each short-axis end.
The spaces near the corners are larger, but they do not increase the nearest 0.5-inch side gap. If your packing method requires a continuous protective layer around the circumference, evaluate its narrowest position rather than averaging the surrounding empty area.
Include edge protection in the diameter once
Suppose a hypothetical bare object is 15 inches in diameter and its selected protection extends 0.75 inch beyond the edge all around. The assembled diameter becomes 15 + 0.75 + 0.75 = 16.5 inches. This is an assumed component dimension, not a recommended protection thickness.
Use 16.5 inches for the footprint screen. Do not add that same edge protection again as a separate clearance allowance. Measure backing and face protection in the height direction as well; a diameter calculation says nothing about the resulting stack height.
Check the centered assembly in a sample
Place the complete pack in the erected mailer and confirm its intended position, contact points and closure. Include any rectangular backing or insert: if it extends beyond the circle, its own length and width can become the controlling footprint. A round main product does not always produce a round finished pack.
Record the diameter, maximum packed height and support arrangement together. MFL22182 is supplied in bundles of 25; choose quantities only after the pack is approved. Review the exact mailer specification and use the mailer fit test to document the assembly. Dimensional clearance alone does not establish transit protection.