#10 Envelopes: Their Definition, Dimensions, & Uses

What You Need to Know about Business-Sized Envelopes

Flock of birds flying in email envelope formation
A #10 Envelope, Also Known as a "Business-Sized" Envelope. Image (c) Tim Robberts / Getty Images

Definition and Dimensions of a #10 Envelope:

#10 envelopes are standard business-sized envelopes which measure 4 1/8 x 9 1/2 inches. They are designed to hold a standard 8 1/2 x 11-inch piece of paper folded into three sections, making them ideal for sending invoices, checks, or other business letters. The #10 envelope is also known as a standard business envelope, a business-sized envelope, or a standard envelope.

Want to see how to fold a letter to fit a #10 envelope? Check out this YouTube video.

Along with letter-sized envelopes, #10 envelopes are the most commonly used in America. Letter-sized envelopes are narrower and longer than #10s, more square-shaped. #10s are longer and more rectangular.

How to Make Your Own #10 Envelopes:

Need a #10 envelope in a hurry, and don't want to run out to the store? Or maybe you'd like to save money by turning a regular piece of paper into the envelope you need?

As it turns out, you can easily create your own #10 envelope with nothing but a glue stick, a ruler, some scissors, your printer, and this envelope folding tutorial from Instructables.

It might take a little practice to get these right, but they give you 

Using #10 Envelopes to Enter Sweepstakes:

If you want to enter mail-in sweepstakes, #10 envelopes are one of the essential supplies you'll need to get started (here are some of the others).

Many sweepstakes specify in their rules that you'll need to send your entries in a standard business-sized envelope to enter.

Be sure to follow the rules carefully, because using the wrong-sized envelope could disqualify you from the sweepstakes and destroy your chance of winning.

Where to Buy #10 Envelopes (Cheap):

#10 envelopes are ubiquitous, which means that you have ample opportunity to find them on sale, cheap.

Here are some of the places to check to see where you can get the best prices available to you:

  • Specialist online envelope shops like Envelopes.com
  • Large online retailers like Amazon
  • Big box retailers like Walmart or KMart
  • Office supply stores like Staples or Office Depot
  • Grocery and drug stores
  • Warehouse stores like Sams Club or Costco

By shopping around these locations, you can save money buying #10s. Don't forget to use coupons and gift cards to reduce your envelope costs even more, when you have the opportunity.