Flat Mailers

Sizing Note: All dimensions shown below are outside dimensions. Allow additional room for the thickness of your product when selecting a mailer size.
Image SKU Dimensions Color/Print Style Mailers/Case
Price/Case
1 5 10
Add To Cart
5 1/8 x 5 1/8 PH-231103 5 1/8 x 5 1/8" White Self-Seal Flat Mailers 200
$51.31 $51.31 $51.31
6 x 6 PH-231109 6 x 6" Kraft Self-Seal Flat Mailers 200
$59.73 $59.73 $59.73
6 x 6 PH-231111 6 x 6" White Flat Mailers 200
$54.69 $54.69 $54.69
6 x 6 PH-231113 6 x 6" White Self-Seal Flat Mailers 200
$61.60 $61.60 $61.60
6 x 8 PH-231115 6 x 8" Kraft Flat Mailers 100
$29.87 $29.87 $29.87
6 x 8 PH-231117 6 x 8" Kraft Self-Seal Flat Mailers 100
$36.40 $36.40 $36.40
6 x 8 PH-231119 6 x 8" White Self-Seal Flat Mailers 25
$15.23 $15.23 $15.23
6 x 8 PH-231121 6 x 8" White Flat Mailers 100
$31.73 $31.73 $31.73
6 x 8 PH-231123 6 x 8" White Self-Seal Flat Mailers 100
$42.13 $42.13 $42.13
7 x 9 PH-231129 7 x 9" Kraft Self-Seal Flat Mailers 100
$49.80 $49.80 $49.80
7 x 9 PH-231131 7 x 9" White Flat Mailers 100
$41.87 $41.87 $41.87
7 x 9 PH-231133 7 x 9" White Self-Seal Flat Mailers 100
$44.71 $44.71 $44.71
8 x 6 PH-231137 8 x 6" White Utility Flat Mailers 200
$65.61 $65.61 $65.61
9 x 6 PH-231143 9 x 6" White Side Loading Flat Mailers 200
$107.33 $107.33 $107.33
9 x 7 PH-231145 9 x 7" White Utility Flat Mailers 200
$86.95 $86.95 $86.95
9 x 11 1/2 PH-231147 9 x 11 1/2" White Flat Mailers 100
$67.95 $67.95 $67.95
9 x 11 1/2 PH-231149 9 x 11 1/2" Kraft Flat Mailers 100
$47.56 $47.56 $47.56
9 x 11 1/2 PH-231151 9 x 11 1/2" Kraft Self-Seal Flat Mailers 100
$49.60 $49.60 $49.60
9 x 11 1/2 PH-231153 9 x 11 1/2" White Self-Seal Flat Mailers 25
$20.59 $20.59 $20.59
9 x 11 1/2 PH-231155 9 x 11 1/2" White Flat Mailers 100
$49.47 $49.47 $49.47
9 x 11 1/2 PH-231157 9 x 11 1/2" White Self-Seal Flat Mailers 100
$53.25 $53.25 $53.25
9 1/2 x 6 PH-231159 9 1/2 x 6" White Utility Flat Mailers 200
$77.37 $77.37 $77.37
9 3/4 x 12 1/4 PH-231165 9 3/4 x 12 1/4" Kraft Flat Mailers 100
$49.47 $49.47 $49.47
9 3/4 x 12 1/4 PH-231167 9 3/4 x 12 1/4" Kraft Self-Seal Flat Mailers 100
$52.27 $52.27 $52.27
9 3/4 x 12 1/4 PH-231171 9 3/4 x 12 1/4" White Self-Seal Flat Mailers 25
$21.93 $21.93 $21.93
9 3/4 x 12 1/4 PH-231173 9 3/4 x 12 1/4" White Flat Mailers 100
$54.03 $54.03 $54.03
9 3/4 x 12 1/4 PH-231175 9 3/4 x 12 1/4" White Self-Seal Flat Mailers 100
$55.87 $55.87 $55.87
10 x 7 3/4 x 1 PH-231177 10 x 7 3/4 x 1" White Gusseted Flat Mailers 100
$70.60 $70.60 $70.60
11 x 13 1/2 PH-231183 11 x 13 1/2" Kraft Flat Mailers 100
$60.24 $60.24 $60.24
11 x 13 1/2 PH-231185 11 x 13 1/2" Kraft Self-Seal Flat Mailers 100
$67.20 $67.20 $67.20
11 x 13 1/2 PH-231187 11 x 13 1/2" White Self-Seal Flat Mailers 25
$24.56 $24.56 $24.56
11 x 13 1/2 PH-231189 11 x 13 1/2" White Flat Mailers 100
$60.67 $60.67 $60.67

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Flat Mailers for Documents, Prints and Other Thin Products

Flat mailers use chipboard or paperboard construction to enclose documents, photographs, certificates and other thin products without the depth of a corrugated box. The assortment includes standard, self-seal, utility, gusseted and side-loading formats. Dimensions are stated as outside dimensions, so product thickness must be included when selecting a size.

Allow for Thickness and Loading Direction

Measure the full product stack with sleeves, backing boards or interleaving, then test it against usable interior space. A mailer that matches the document’s nominal length and width may be too small once thickness and seams are considered. Avoid forcing contents through an opening, which can bend corners or weaken the closure.

For products needing corrugated structure or a set interior depth, compare corrugated literature mailers. Side-loading styles may simplify insertion of wider pieces, while gusseted formats provide additional capacity for compatible stacks.

Select Caliper, Closure and Surface Deliberately

Chipboard caliper helps compare material thickness, but it is not a universal bending or puncture rating. Review the product’s rigidity, value and carrier handling, and add an internal stiffener when required. Kraft, white and black finishes affect presentation and label contrast rather than establishing strength or moisture resistance.

Self-seal construction can speed closure, but test adhesion on clean stock under the expected temperature and storage conditions. A closed flat mailer is not automatically waterproof, tamper-evident or suitable for photographs and archival materials. Validate the complete pack and any controlled material requirements separately.

Flat Mailer Style Comparison

Style Useful When Check
Standard or utility General thin documents and prints Usable space and closure method
Self-seal Packing speed and adhesive closure matter Adhesion and storage conditions
Gusseted A thicker compatible stack needs capacity Expanded thickness and seam stress
Side loading Broad items insert more easily through an edge Opening clearance and corner protection

Flat Mailers FAQs

Are flat-mailer dimensions inside or outside?

This selection states outside dimensions, so allow additional room for product thickness and the mailer seams.

Does higher chipboard caliper prevent bending?

It can add stiffness, but complete performance depends on size, contents, handling and any internal backing.

When should I use a gusseted flat mailer?

Use one for a compatible thicker stack after confirming usable expansion and closure.

Are flat mailers moisture-resistant?

Do not assume so. Verify the exact construction and add suitable protection when moisture exposure is expected.

Need Help Choosing Flat Mailers?

Packaging HERO can help you compare outside size, usable capacity, caliper and loading style.

Contact Packaging HERO