What Are Non-Machinable Stamps? (Meaning, Value + More)

Part of what makes USPS so efficient is its mail sorting machines. In fact, these machines can sort up to 36,000 pieces of mail per hour! They work great when the mail is standard-sized, but what happens when that’s not the case?

Mailpieces that don’t fit into machines need to have their stamps hand-canceled. Not surprisingly, that takes more time.

When this happens, USPS charges a surcharge payable with Non-Machinable stamps. So, if you have questions about Non-Machinable stamps, I’ve researched them in-depth!

What Are Non-Machinable Stamps?

Non-Machinable stamps are stamps issued by USPS that cover postage on First-Class domestic mailpieces that don’t meet the designated sizing standards. Examples of Non-Machinable items include square greeting cards, rigid letters, or lumpy letters containing pens or keys. Such things don’t fit into sorting machines and must be hand-canceled, resulting in a surcharge.

If you have more questions about Non-Machinable stamps, like how much they cost and where you can buy them, keep reading to find all the answers you need!

What Is Non-Machinable Mail?

Before getting into what Non-Machinable stamps are, it’s helpful to have some background about Non-Machinable mail.

In the simplest terms, Non-Machinable mail is any piece of mail that USPS’ machines can’t sort due to an irregular size or shape.

That said, square greeting cards are the most common example. Further, USPS considers a standard-sized letter to be:

  • Rectangular
  • At least 3½ inches high x 5 inches long x 0.007 inches thick.
  • No more than 6⅛ inches high x 11½ inches long x ¼ inch thick.

So, letters that don’t meet these criteria slow down and sometimes even jam machines.

To avoid any mechanical issues, USPS employees remove unusually-sized mail and hand-cancel the stamps.

Not surprisingly, hand sorting takes longer than machine sorting. As a result, USPS tacks on a surcharge for mail that doesn’t adhere to standard mail sizes (i.e., Non-Machinable mail).

What Is The Non-Machinable Surcharge For First-Class Mail?

As mentioned above, unusually sized or shaped mailpieces must be processed outside of the standard, automated mail process.

In most cases, they’re hand-sorted by USPS employees, making them more expensive to process, hence the surcharge.

That said, USPS adds a Non-Machinable surcharge to First-Class Mail with any of the following criteria:

  • A letter with an aspect ratio (length divided by height) of less than 1⅓ or more than 2½ (square envelopes)
  • A letter that’s more than 4¼ inches high or 6 inches long and is less than 0.009 inches thick
  • A letter with clasps, strings, buttons, or similar closure devices
  • A letter that’s too rigid
  • A letter with a delivery address parallel to the shorter side of the mailpiece
  • A letter that contains items such as pens, pencils, or keys that create an uneven thickness
  • A letter that is poly-bagged, poly-wrapped, enclosed in any plastic material, or has an exterior surface made of a material that’s not paper

Currently, the Non-Machinable surcharge is $0.30.

How Much Do Non-Machinable Stamps Cost?

Currently, Non-Machinable stamps sell for $0.88, making them $0.30 more expensive than standard-sized First-Class letters.

Are Non-Machinable Stamps Forever Stamps?

Like Forever Stamps, stamps with the words “Non-Machinable Surcharge” written on them will always be valid for the current Non-Machinable surcharge.

In other words, if you buy Non-Machinable stamps today and USPS increases the price tomorrow, you’ll still be able to use the stamps you purchased even though you paid less than the current value.

Can I Use A Non-Machinable Stamp On Regular Mail?

Can I Use A Non-Machinable Stamp On Regular Mail? USPS

Technically speaking, yes, you can use Non-Machinable stamps for regular mail.

That said, Non-Machinable stamps cover the First-Class postage rate for a one-ounce letter plus whatever the current Non-Machinable surcharge is.

Also, if your letter is standard-sized, there’s no need to pay the surcharge. Therefore, if you use a Non-Machinable stamp on your letter, you’ll be overpaying for no reason.

If I Don’t Have A Non-Machinable Stamp, Can I Use Two Forever Stamps?

Yes, you can use two Forever Stamps to cover the Non-Machinable surcharge. Currently, Forever Stamps cost $0.58, so if you add two together, that covers $1.16 worth of postage.

Further, Non-Machinable stamps cost $0.88. Therefore, two Forever Stamps is more than enough postage to cover the surcharge.

So, while you can use multiple Forever Stamps instead of a Non-Machinable stamp, you’ll be overpaying for postage.

Thus, it makes more financial sense to use a Non-Machinable stamp if you can get your hands on one.

Where Can I Buy Non-Machinable Stamps?

You can buy Non-Machinable stamps at your local Post Office, on the USPS website, or over the phone by calling 1-800-STAMP-24 (1‑800‑782‑6724).

If you’re buying stamps in person, you can purchase them individually. However, if you are buying Non-Machinable stamps online or over the phone, you’ll need to buy a sheet of 20.

How Much Are Non-Machinable Stamps?

Currently, Non-Machinable stamps sell for $0.88 each, which includes the $0.58 First-Class postage fee plus the $0.30 Non-Machinable surcharge.

In comparison, a sheet of 20 Non-Machinable stamps retails for $17.60.

What Do Non-Machinable Stamps Look Like?

Non-Machinable stamps are sometimes called butterfly stamps because they all feature butterflies.

That said, this decision resulted from a 2010 collaboration between USPS and the Greeting Card Association.

Further, both organizations wanted to make it easier for consumers to know if they were putting enough postage on their heavier or irregularly-shaped envelopes.

Therefore, USPS agreed to feature butterflies on all of its Non-Machinable stamps, while greeting card companies started printing a butterfly icon on cards requiring a Non-Machinable stamp.

Currently, USPS features two butterfly stamps; one features the California Dogface butterfly, the other the Colorado Hairstreak butterfly.

In addition to the butterfly image, both stamps feature the words “USA,” “Non-Machinable Surcharge,” and the year of the stamp’s release.

If you want to know more, you can also read our posts on what are military stamps, what are priority mail stamps, and what are semi-postal stamps.


Whether you’re sending a funky birthday card or a unique wedding invitation, USPS’ Non-Machinable stamps are there to help make sure your item gets to its destination safely for an affordable price.

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Marques Thomas

Marques Thomas graduated with a MBA in 2011. Since then, Marques has worked in the retail and consumer service industry as a manager, advisor, and marketer. Marques is also the head writer and founder of QuerySprout.com.

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