How many stamps do I need? And where to buy?

The number of stamps you put on letters or packages depends on the envelope size and its weight. If you don't have the time to go to a post office before calculating how many stamps you need, here's a guide that will help you.

How many stamps do I need?

There's no easy answer to how many stamps your mail item needs because it's dependent on many different things such as weight, size, and the receiver's location. In most cases, a single postage stamp will suffice to mail a letter. That changes for irregularly shaped envelopes, heavy envelopes, or oversized envelopes.

When figuring out how many stamps you need to mail your letter or postcard, your postage costs will depend on the shape and size of your mail. If your envelope isn't flat, it won't fit in automated processing equipment, and you will be charged more.

• Standard letters. If your letter is a standard-sized envelope and weighs 3.5 ounces or less, you will need one stamp.
• Large envelopes. This includes 9x12, legal, and manila envelopes, Two stamps are needed for the first ounce, and postage will be an additional $0.20 cents after.
• International mail. For mail going outside of the United States, you can use Forever Stamps or a Global Forever Stamp. If your letter is one ounce or below, you will need one Global Forever stamp or three Forever Stamps.
• Packages. The number of required stamps depends on the weight and size of the package. Usually, the first four ounces need a minimum of $3.80 in postage, with more postage as weight increases. Shipping costs vary depending on weight, or you can purchase a priority mail box, which ships at a flat rate if it fits inside the USPS-produced boxes.

It's not just the weight that matters. All postcards and envelopes must be rectangular. If you're sending square-shaped stationery or a specialty envelope, you should put an extra stamp on it.

Still not sure? The U.S. Postal Service (USPS) has a postage price calculator here.

How many Forever Stamps do I need?

Forever Stamps, created in 2007, are postage not tied to a fixed price, so they remain valid to mail letters even when rates increase. Basically, they are stamps with grandfathered pricing.

If you have Forever Stamps, you calculate them as worth the current postage rate, even if you bought them before the rate increased.

Where to buy stamps online

The U.S. Postal Service has an online store of its stamp collection where you can purchase as many stamps as you'd like. Or there are other online retailers, such as Stamps.com, that sell stamps and allow you to buy and print postage from your home.

If you don't want to purchase online, you can buy stamps at your local post office or by phone at 1-800-STAMP-24.

Additionally, you can often purchase a book of stamps at gas stations, grocery stores, and pharmacies.

The modern way of managing your mail

Heard of a virtual mailbox? It's like your home mailbox but does the work for you while giving you an added layer of privacy and security.

A virtual mailbox from Earth Class Mail, a LegalZoom company, allows you to view mail sent to a virtual mailing address of your choice as it comes to our secure processing facility. You can set up your account so that we automatically scan your mail items, and you only have to view and manage the mail scanned in your account.

With your account, you can sort, save, or share those PDFs, so you can easily organize all your incoming mail. Virtual mailboxes are especially helpful if postal workers have difficulty delivering mail to your home address.

How many stamps are in a book?

The standard stamp book for first-class mail postage includes 20 first-class stamps that can be applied to envelopes and also on first-class postage. You can also purchase Forever Stamps, which also have 20 stamps in a book. Each year the USPS releases a 64-page book called Collective Stamp Book.

How much is a postage stamp?

Postage costs depend on the mail item size. Stamp prices for standard postage start at $0.40 for the standard-sized, rectangular postcard; the cost of a stamp for a regular envelope starts at $0.58; oversized postcards need stamps that start at $0.58; and oversized, square, or unusual envelope stamps start at $0.88. For large envelopes and small packages, prices range between $1.16 and $4.50. You will pay extra for nonstandard packages. For sizes between 22 and 30 inches long, add an additional $4.00 to costs. For packages longer than 30 inches and 2 cubic feet, there will be an additional fee of $15.00.

Tip: Check your local post office for updated pricing.

To learn more about Earth Class Mail's offerings, go here.