USPS® Large Envelopes and Mailers

Sending a CD, magazine, legal document, or other item in a large envelope? Make sure the dimensions and prices are right before you send.

What are large envelopes?

The term “large envelopes,” also known as flat mail, refers to First-Class Mail® sent in envelopes that exceed a certain size and are used to send items and documents you wouldn’t want folded. To send large envelopes, you need postage stamps and access to a postage meter, or you can ditch the postage meter and print postage online with us.

What are the dimensions of a large USPS envelope?

Large envelopes refer to First-Class Mail sent in envelopes that exceed either 6⅛″ in height, 11½″ in width, or ¼″ in thickness. Typically, large envelopes are large enough to fit a standard, unfolded 8½″ x 11″ sheet of paper. Envelopes used for flat mail cannot be more than ¾″ thick, 12″ high, 15″ long, or weigh more than 13 ounces. USPS considers any envelope bigger than this size to be a package, so you’ll want to monitor your dimensions.

USPS postage rates for large envelopes

If your large envelope exceeds USPS’ dimensions, it will be subject to higher prices. Pricing depends on the weight of the envelope with prices starting at $1.50 and increasing by $0.27* for each additional ounce, and your large envelopes sent in the U.S. will generally arrive within three business days.

*For First-Class mail flat, each additional ounce, 1 oz. – 4 oz., is $0.27. For 5 oz. – 9 oz., each additional ounce costs $0.28. For 10 oz. – 13 oz., each additional ounce costs $0.30.

The benefits of sending large envelopes with us

We’ll tell you exactly how much postage is required to send your mail to any domestic or international location, and you can print USPS-approved postage and address labels from the comfort of your own home or office. Send the simple way.

Start mailing today

Print your own postage in seconds without the hassle of expensive hardware or postage math. Find the plan that works for your business and start saving today.

*For First-Class mail flat, each additional ounce, 1 oz. – 4 oz., is $0.27. For 5 oz. – 9 oz., each additional ounce costs $0.28. For 10 oz. – 13 oz., each additional ounce costs $0.30.