Introduction
A catalog envelope is a large, open-end envelope designed to carry flat, unfolded content — catalogs, annual reports, magazines, and marketing booklets. Unlike a #10, which folds a letter, a catalog envelope keeps the contents flat and intact.
The two dominant sizes are 9×12 and 10×13, with 6×9 as the smaller booklet option. This guide covers the sizes, the open-end design, thickness room, and the flat-mail postage rules that govern what they cost to send.
Catalog Envelope Sizes
Catalog envelopes come in a few standard large sizes.
| Size | Dimensions | Holds |
|---|---|---|
| 6×9 | 6″ × 9″ | Small booklet, brochure |
| 9×12 | 9″ × 12″ | Flat 8½×11, catalog |
| 10×13 | 10″ × 13″ | Thick catalog, annual report |
9×12 is the standard catalog size; 10×13 adds room for thicker or oversized content.
| Use case | Size |
|---|---|
| Standard catalog | 9×12 |
| Annual report | 9×12 or 10×13 |
| Thick catalog | 10×13 |
| Small brochure | 6×9 |
Open-End Design
Catalog envelopes use an open-end design — the flap is on the long side.
| Trait | Open-end (catalog) |
|---|---|
| Flap position | Long side |
| Opening | Wide, easy insert |
| Contents | Flat, unfolded |
This contrasts with open-side (booklet) envelopes:
| Factor | Open-end | Open-side |
|---|---|---|
| Flap | Long side | Short side |
| Insert | Flat documents | Booklets |
| Typical | Catalog, report | Card, booklet |
Thickness Room
Catalog envelopes need extra room for stacked pages.
| Content | Thickness note |
|---|---|
| Thin catalog | Standard gusset or none |
| Thick catalog | Needs room to slide |
| Annual report | Multiple pages |
The envelope should be sized so the catalog slides in without forcing:
| Rule | Why |
|---|---|
| Extra room | Easy insert |
| Stay within flat limits | Postage class |
| No bulging | Avoid parcel rate |
Paper and Weight
Catalog envelopes need durable stock to protect contents in transit.
| Weight | Feel | Use |
|---|---|---|
| 28 lb | Standard | Light catalogs |
| 32 lb | Substantial | Standard catalogs |
| 40 lb+ | Rigid | Thick, valuable |
Heavier stock protects contents but raises postage weight:
| Choice | Trade-off |
|---|---|
| Light stock | Cheaper, less protection |
| Heavy stock | More protection, heavier |
| Balance | Match to contents |
For paper fundamentals, see our envelope paper types guide.
Flat-Mail Postage Rules
Catalog envelopes mail as flats — a specific postal class with its own limits.
| Class | Dimensions | Cost |
|---|---|---|
| Letter | Up to 6⅛”×11½” | Lowest |
| Flat | To 12″×15″, ¾” thick | Mid |
| Parcel | Over flat limits | Highest |
The key is staying within flat limits:
| Limit | Keep within |
|---|---|
| Size | 12″ × 15″ |
| Thickness | ~¾” |
| Uniformity | Even |
A thick catalog that exceeds ¾” or becomes non-uniform tips into parcel rates — a significant cost jump.
Use Cases
Catalog envelopes serve specific high-value mailings.
| Use case | Envelope |
|---|---|
| Product catalogs | 9×12 |
| Annual reports | 9×12 or 10×13 |
| Magazines | 9×12 |
| Marketing booklets | 6×9 or 9×12 |
| Thick documents | 10×13 |
For the single-size 9×12 deep-dive, see our 9×12 envelope standards guide; for the broader large-envelope picture, our large envelopes piece.
Conclusion
Catalog envelopes are the open-end, flat-content carriers — 9×12 for standard catalogs and reports, 10×13 for thicker content, 6×9 for smaller booklets. Choose open-end design for easy flat insertion, size for thickness room, and stay within flat-mail limits to avoid parcel rates. For the single-size deep-dive, see our 9×12 envelope standards guide.
Mailing catalogs or annual reports? Request a quote.