Business Envelopes: All Sizes

Every envelope size used in U.S. business and personal mailing is in this catalog. From compact coin envelopes at 2 1/4 x 3 1/2 inches up through oversized 10 x 15 Tyvek mailers, organized by size, closure type, and color so you can filter directly to what your mailing program needs. Business Envelopes has supplied direct to offices, nonprofits, law firms, schools, and small businesses since 1997. Free ground shipping on every order across the contiguous 48 states. No minimums. Same or next day production on blank stock.

Standard Business Envelope Sizes: The Complete Reference

The U.S. commercial envelope numbering system assigns a number designation to each size in the standard letter-format range. Here's every size we carry with dimensions and primary use cases:

#1 Coin Envelopes — 2 1/4 x 3 1/2 inches

The smallest standard coin envelope. Single coins, stamps, small gemstones, watch parts, seeds, and tiny hardware. Short-side flap opens on the narrow edge for easy small-item insertion. Available in white and brown kraft.

#7 Coin Envelopes — 2 7/8 x 4 7/8 inches

The most widely used coin envelope size. Holds multiple coins, keys, SD cards, small jewelry, folded bills, and electronic components. Short-side flap. Available in white and brown kraft with gum flap and peel-and-seal closures.

#6 3/4 Envelopes — 3 5/8 x 6 1/2 inches

The compact commercial letter envelope. Fits a letter sheet folded into quarters, half-sheet documents, and short correspondence. Fits inside a #9 or #10 as a compact return enclosure. Qualifies for USPS letter-rate postage.

#9 Envelopes — 3 7/8 x 8 7/8 inches

Sized precisely to nest inside a #10 with a quarter inch of clearance on each side. The standard return mail enclosure for billing programs, nonprofit appeals, and any outgoing piece that includes a reply envelope. Available in plain, tinted, window, and starburst.

#10 Envelopes — 4 1/8 x 9 1/2 inches

The standard U.S. business envelope. Holds an 8.5 x 11 sheet folded into thirds. The most ordered size in the catalog. Available in more configurations than any other size: plain, tinted, window, tinted window, self-seal, peel-and-seal, double window, wove colored, and starburst.

#12 Envelopes — 4 3/4 x 11 inches

One step above the #10 in capacity. Handles thick multi-enclosure correspondence, check-plus-statement packets, and documents that make a #10 look overstuffed. Still qualifies for letter-rate postage. Available in plain and window configurations.

#14 Envelopes — 5 x 11 1/2 inches

The largest standard commercial letter envelope. Holds a legal-size 8.5 x 14 sheet folded into thirds where a #12 cannot. Still qualifies for USPS letter-rate postage at 5 inches tall. Used by law firms, insurance carriers, and financial practices for thick outgoing correspondence.

Business Size Envelopes: Flat-Document Formats

For documents that can't be folded, the catalog moves into flat-document catalog and booklet formats. These mail as USPS flats at higher flat-mail postage rates.

6 x 9 Envelopes

Holds an 8.5 x 11 sheet folded in half, 5 x 7 photos, and small booklets. At exactly 6 inches tall, clears the USPS letter-rate threshold on light contents, which gives it a meaningful postage cost advantage over larger flat formats. Available in white booklet, white open-end, brown kraft, clasp, Tyvek, and starburst formats.

9 x 12 Envelopes

The standard flat-document mailer. Holds an 8.5 x 11 sheet completely flat. Used for contracts, certificates, photos, reports, and any correspondence where document condition on arrival matters. Available in white booklet, white open-end, white full-view window, brown kraft, clasp, Tyvek, and starburst formats.

10 x 13 Envelopes

One inch larger than the 9 x 12 on each dimension. Fits legal-size sheets flat and accommodates thicker document stacks. Available in white booklet peel-and-seal, white open-end, brown kraft clasp, and Tyvek formats.

Small Business Envelopes: Ordering Without Minimums

There's no minimum order on any size in this catalog. That matters for small businesses and organizations that need professional-quality envelopes without committing to a case quantity they don't have storage for. You can order a single box of #10s, a small quantity of 9 x 12 flat mailers, and a few hundred coin envelopes in the same order, all ship together, all free. Bulk pricing applies automatically as quantities increase, so the per-unit cost drops without any account setup or negotiation required.

Blank stock ships same or next business day. Custom printed orders, with your logo and return address printed directly on the envelope stock, ship in 7 to 10 business days from proof approval. Artwork stays on file for reorders. For volume programs spanning multiple sizes, request a bulk quote here and we'll price the full scope the same day.

Why Plain Business Envelopes From a Dedicated Supplier Beat the Office Supply Store

Retail pricing on envelopes reflects distribution overhead: the retailer's margin, the distributor's margin, the shelf space, and the packaging for a consumer-facing product. When you order direct from us, those layers don't exist. The price reflects the product and the shipping, nothing else. The 24 lb white wove #10 that costs multiples per unit at a chain store costs significantly less per unit ordered in any reasonable quantity from a dedicated envelope supplier. The stock is the same. The print compatibility is the same. The gum flap adhesive is the same. The only difference is what you pay for it and how fast it arrives.

We've been direct-to-business since 1997. No retail channel, no distributor network. Orders go from our facility in Monroe, NY directly to your door. For resellers and corporate accounts with consistent recurring volume, the wholesale pricing program provides structured discounts without requiring a promo code on every order. Browse the full product catalog for every size, style, and configuration, or use the size filters above to navigate directly to what you need.

Frequently Asked Questions About Business Envelope Sizes