How Many Stamps Fit on a 9″ x 12″ Envelope?

A 9-inch by 12-inch envelope is categorised as a big envelope by the United States Postal Service (USPS). What does this mean for postage, though? You might be wondering how many stamps you’ll need to attach to your outgoing mail if you need to mail something that is somewhat flat but also doesn’t fit in a conventional letter envelope.

To guarantee that the cost of the envelope is paid and that it arrives securely, find out more about how many stamps to place on a 9×12 envelope.

Postage on 9 x 12 Envelopes Weighing More Than an Ounce

A 912 envelope weighing no more than an ounce can be sent for the price of two First Class stamps. Although the cost to ship a large envelope is only $1.00, a First Class stamp is $0.55, therefore utilising stamps actually costs you an additional $0.10.

You will require more stamps if your 9 x 12 envelope weighs more than 1 ounce; the quantity of stamps required is determined by the overall weight. You must pay $0.20 for each additional ounce. Therefore, the cost of mailing a parcel weighing 4.3 ounces is $1.80, or four First Class stamps.

Use the USPS postage calculator to make sure you’re putting the right amount of stamps on your envelope if you’re unclear of the charges. There are other postal options besides First Class stamps, though.

Purchasing Postage for a 9-by-12-Inch Envelope

Your 912 envelope can be used to mail various papers or thin goods; simply apply two First Class stamps to it before dropping it into your mailbox. Then it will be retrieved and delivered by your mail carrier.

Remember that you might slightly overspend if you take this course of action. If you don’t mind making the trip to your local post office, you can also have your parcel weighed and paid for there with a debit card, credit card, cash, or other acceptable method of payment.

This approach helps you avoid paying too much, but it can mean standing in line. When you choose to visit the post office, you may not be spending a lot on postage, but you will incur a time cost for the minor inconvenience.

You might decide to calculate postage at home as a result. Weighing and paying are simple thanks to a variety of services and useful items, but they might not be effective if you’re only mailing one item and aren’t shipping things frequently.

You could buy the packaging supplies you require based on your shipping procedures, for instance, if you’d prefer avoid the post office lineups while keeping your First Class stamps. Then, you might calculate your shipping expenses and print a label using an online postage provider.

Users can quickly weigh their mail and print shipping labels using the USPS’s Click-N-Ship service. As an alternative, offers clients discounts on postage while also giving away free postal scales.

Additional Elements That May Impact Your Envelope’s Postage Cost

You can wind up spending more to have your large envelope delivered to your desired location if it isn’t perfectly flat. Flat envelopes can be automatically sorted using one of the various machines at the post office, but employees must manually sort lumpy or rigid envelopes. This raises the price because it necessitates a small amount more labour during the process.

Consider the 2-ounce 9-by-12-inch envelope as an example. You still want to deliver it, but it’s a touch lumpy. For mailing your goods, you might have to spend $3.85 ($2.05 extra). According to your destination and the kind of odd package you’re trying to mail, specific additional expenses change.

However, 912 envelopes are an excellent size for quickly sending a wide range of things. You can ship the following products most frequently in large 9-by-12 envelopes:



game consoles



little works of art

Since the majority of these items are flat, mailing them in big envelopes rather than boxes is excellent. Remember that when mailing products in bigger 912 envelopes, flat and flexible are ideal (and most cheap).

Options for Quicker Mailing Your 912 Envelope

You might not want to use a First Class stamp if you need your package to reach its destination as soon as possible. There is a quicker option, even though the proper number of First Class stamps may securely deliver your large envelope to its destination in one to three business days (at least for domestic mailing).

Priority Mail Express 2-Day from the USPS ensures arrival on the same day or within two days of shipping. When you consider that the USPS processes close to 500 million pieces of mail per day, that is a remarkable turnaround. However, you should be prepared to pay more for this kind of accelerated service.

With First Class postage, a flat, flexible big envelope weighing one ounce might cost you $1.10. However, the identical box could run you $26.60 if it were sent via Priority Mail Express 2-Day. Still, for individuals who need to move products rapidly, the USPS offers valuable and extraordinary services. Spending more money for Priority Mail delivery when something needs to arrive quickly might be worthwhile.

Misha Khatri
Misha Khatri is an emeritus professor in the University of Notre Dame's Department of Chemistry and Biochemistry. He graduated from Northern Illinois University with a BSc in Chemistry and Mathematics and a PhD in Physical Analytical Chemistry from the University of Utah.


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