Regular Envelopes come in a wide range of sizes, colors, and styles. They typically feature a solid front with no window, and a basic flap on the back. Nearly all businesses need #10 envelopes, which measure 4 1/8" by 9 1/2" and hold a standard sheet of paper folded in thirds.
The standard #6 3/4 remittance envelope is 3 5/8 x 6 1/2 inches (metric size 92mm x 165mm) when closed. Other common sizes are the #9 remittance at 3 7/8 by 8 7/8 inches and #10 remittance at 4 1/8 x 9 1/2 inches.
Envelopes are available in many different sizes and types of paper. They can even be custom-made. Castle Press stocks a range of standard envelope sizes.
Also see International Standard Paper & Envelope Sizes. Letter, legal, ledger, and tabloid are by far the most commonly used of these for everyday .
Standard envelope sizes â€“ regular and widow envelope sizes and downloadable envelope templates.