How Many Stamps Do I Need?

How to Send a Letter

Blog author Alex Cook's photo

By Alex Cook

Updated January 2024
Last postage increase January 21, 2024
Photo of an old envelope reading 'Postage for United States'

The United States postal system is an incredible public service. For only $0.68, a letter can be sent to anywhere in the United States to arrive in 1-3 days! The first $0.68 covers up to 1 ounce. After that, add $0.24 per ounce up to 3.5 ounces.

If you want to learn about how to send a letter, we're here to help. Check out our guide on stamps per ounce. If you have any questions, don't hesitate to leave a comment. (We read and respond to all comments.)

How Many Stamps Do I Need For a Letter to the United States?

The number of stamps you'll need depends on the size and weight of your letter. See how to send a letter.

Below are the rates for standard envelopes for normal envelopes like a letter or birthday card, no bigger than 11.5” x 6+⅛” (see envelope requirements). The postal service refers to large envelopes as 'flats.' — View rates for flats.

Weight Postage
1 ounce ($0.68) One Domestic Forever stamp ($0.68)
USA Forever Stamp, USA flag design
2 ounces ($0.92) One Domestic Forever stamp, and one 24¢ Additional Ounce stamp ($0.92)
USA Forever Stamp, USA flag designUSA additional ounce forever stamp, president heads wearing flag-themed tophats

Or you can overpay by $0.44 using two Domestic Forever stamps ($1.36)
USA Forever Stamp, USA flag designUSA Forever Stamp, USA flag design
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3 ounces ($1.16) One Domestic Forever stamp, and two 24¢ Additional Ounce stamps ($1.16)
USA Forever Stamp, USA flag designUSA additional ounce forever stamp, president heads wearing flag-themed tophatsUSA additional ounce forever stamp, president heads wearing flag-themed tophats

Or you can overpay by $0.20 using two Domestic Forever stamps ($1.36)
USA Forever Stamp, USA flag designUSA Forever Stamp, USA flag design
3.5 ounces ($1.40) Two Domestic Forever stamps, and two 2¢ stamps ($1.40)
USA Forever Stamp, USA flag designUSA Forever Stamp, USA flag designUSA two cent stamps, a meyer lemon next to two lemon halfs cut open, reading USA in the lower left and 2¢ in the upper right in yellow fontUSA two cent stamps, a meyer lemon next to two lemon halfs cut open, reading USA in the lower left and 2¢ in the upper right in yellow font

Or you can overpay by $0.64 using three Domestic Forever stamps ($2.04)
USA Forever Stamp, USA flag designUSA Forever Stamp, USA flag designUSA Forever Stamp, USA flag design
More than 3.5 ounces See rates for flats

How to Send a Letter

1. Measure Your Envelope

For a standard letter (under 3.5 ounces), your envelope must be a minimum 5” x 3.5”, maximum 11.5” x 6+⅛”, and no thicker than 1/4". Most smaller thank-you cards meet the minimum and larger greeting cards are under the maximum, as seen below.

Photo showing three envelopes on a table with a ruler measuring either side. There is a measuring stick that says, 'WEYMOUTH LUMBER COMPANY'. The larger greeting card featured on the right says CAKE ON CAKE ON CAKE.

All of the envelopes pictured meet the size standards. A standard security envelope is 9.5" x 4.25", the typical smaller thank-you note is 5" x 4" (above the minimum) and a larger greeting card 8.5" x 5.25" (under the maximum).

Make sure your envelope is of uniform thickness, rectangular, and bendable. Otherwise, you may have a "non-machinable" envelope and add $0.40 of extra postage. Check out the full list of non-machinable characteristics.

Square envelopes must be a minimum of 5". Square envelopes are considered non-machinable so add the extra $0.40. If you don't add the $0.40 extra, the USPS may return your envelope back to you.

2. Weigh your letter

Use a kitchen food scale to check your envelope’s weight. If you don’t have a scale, Amazon makes a good entry level scale for $12.59 or Walmart sells several inexpensive kitchen scales like this Milleroo scale for $13.36

Round up to the nearest ounce. For example, if your letter weighs 1.21 ounces, you will need postage for 2 ounces. Apply the correct number of stamps per ounce (See stamps per ounce).

If you're sending printed photos, check out our guide on how many stamps are needed to mail 4x6 photos — no scale needed!

3. Address Your Envelope and Add Stamps

A return address typically goes in the upper-left of your envelope and is not required. Your recipient's address should go in the center of the envelope. Stamps go in the upper-right corner of a letter, ideally all in one row. However, the post office will accept your letter even if your stamps go to a second or third line.

Where to Buy Stamps

You can buy stamps at your local USPS post office and online at USPS.com — shipping is just over $1 for a sheet of stamps. Walmart and Amazon also carry stamps, as well as many local banks. Stamps from Amazon aren't a very good deal at $16.18 for a sheet of 20 which you can get for $5.18 less direct from the USPS.

Delivery Speed for Letters to United States

Mail send with stamps isn't tracked and delivery times are not guaranteed, however the typical delivery time is 1-3 days.

How Many Stamps for a Postcard?

Check out our detailed guide on sending postcards.

If you're sending a postcard to United States you'll need one Postcard Stamp for $0.53. You can also overpay using one Forever Stamp for $0.68. Make sure your postcard is:

  • Rectangular (it can't be a square or round)
  • At least 3-1/2 inches high x 5 inches long x 0.007 inch thick
  • No more than 4-1/4 inches high x 6 inches long x 0.016 inches thick

Stamp Price Changes

We check postage rate changes weekly.
Effective January 21, 2024
Announced October 2023
  • The cost of a forever stamp increased from $0.66 to $0.68
  • Postcards increased from $0.51 to $0.53
  • International forever stamps and postcards increased from $1.50 from $1.55
Previous price increases
Announced April 10, 2023
  • The cost of a forever stamp increased from $0.63 to $0.66
  • Postcards increased from $0.48 to $0.51
  • International forever stamps increased from $1.45 from $1.50
Announced October 2022
  • The cost of a forever stamp increased from $0.60 to $0.63
  • Postcards increased from $0.44 to $0.48
  • International forever stamps increased from $1.40 from $1.45
Announced April 2022
  • The cost of a forever stamp increased from $0.58 to $0.60
  • Postcards increased from $0.40 to $0.44
  • Flats increased from $1.00 to $1.16
  • International forever stamps increased from $1.30 from $1.40
  • All international additional ounce rates for both standard letters and flats have increased
Announced May 2021 and effective August 29, 2021, the latest increase took effect in August.
  • The cost of a forever stamp increased from $0.55 to $0.58
  • Postcards increased from $0.36 to $0.40
  • Flats increased from $1.00 to $1.16
  • International forever stamps increased from to $1.30 from $1.20
  • All international additional ounce rates for both standard letters and flats have increased
On January 24, 2021 additional ounces increased from $0.15 to $0.20. Metered mail and postcards increased by 1 cent. There was no change to 1 oz letters and flats. Postcard stamps increased to $0.36.

On January 26, 2020 fates for domestic letters under 3.5 ounces remained the same. Rates for flats (large envelopes) and all global first-class mail increased. Global forever stamps went from $1.15 to $1.20. Rates on additional ounces for flats (large envelopes) went up by $0.05 per additional ounce for domestic flats and changed for international flats as well. Additional ounces for all international first-class mail changed with the base increase from $1.15 to $1.20.

Sending Large Envelopes (Flats)

Below are the rates for sending a large envelope ("flat") . The maximum weight for a standard letter is 3.5 ounces, so use a flat if you're sending more than 3.5 ounces. The base rate for is $1.26. Extra ounces cost more and the maximum weight is 13 ounces. The rates below are sourced directly from the USPS.

Flats must be a minimum of 6-1/8" by 11-1/2", maximum 12" by 15". Unlike standard letters, the maximum thickness is 3/4".

Manilla envelope 8.5x11 showing front and back with sticky flap

A standard 8.5” x 11” manilla envelope is the most common flat size. You can pick up a 100 pack on Amazon for $22.48 ($0.22 each) or 20 pack for $6.43 ($0.32 each). Staples offers a 100-pack for $36.90 ($0.37 each).

You can't use a bubble envelope as bubble envelopes as they are usually more than 1/4" thick. Bubble envelopes are considered a "package / thick envelope" by the USPS. You can purchase a label on PayPal or buy labels in bulk from EasyPost.

How Many Stamps Do I Need For a Large Envelope (Flat) to the United States?

Weight Postage
1 ounce ($1.26) One Domestic Forever stamp, one Postcard stamp, and one 5¢ stamp ($1.26)
USA Forever Stamp, USA flag designUSA postcard stamp, brown shell with teal backgroundUSA five cent stamps, two bundles of purple grapes with green leaves, reading 5¢ in the upper left and USA in the bottom right, both in purple font

Or you can overpay by $0.10 using two Domestic Forever stamps ($1.36)
USA Forever Stamp, USA flag designUSA Forever Stamp, USA flag design
2 ounces ($1.50) Two Domestic Forever stamps, one 10¢ stamp, and two 2¢ stamps ($1.50)
USA Forever Stamp, USA flag designUSA Forever Stamp, USA flag designUSA 10 cent stamp, two red pears reading 10¢ in the upper left and USA in the bottom right, in red fontUSA two cent stamps, a meyer lemon next to two lemon halfs cut open, reading USA in the lower left and 2¢ in the upper right in yellow fontUSA two cent stamps, a meyer lemon next to two lemon halfs cut open, reading USA in the lower left and 2¢ in the upper right in yellow font

Or you can overpay by $0.54 using three Domestic Forever stamps ($2.04)
USA Forever Stamp, USA flag designUSA Forever Stamp, USA flag designUSA Forever Stamp, USA flag design
Brought to you by NanaGram

Text your photos & we'll mail glossy, frameable 4x6 prints to your loved ones!
Photo of a happy NanaGram recipient
3 ounces ($1.74) Two Domestic Forever stamps, one 24¢ Additional Ounce stamp, one 10¢ stamp, and two 2¢ stamps ($1.74)
USA Forever Stamp, USA flag designUSA Forever Stamp, USA flag designUSA additional ounce forever stamp, president heads wearing flag-themed tophatsUSA 10 cent stamp, two red pears reading 10¢ in the upper left and USA in the bottom right, in red fontUSA two cent stamps, a meyer lemon next to two lemon halfs cut open, reading USA in the lower left and 2¢ in the upper right in yellow fontUSA two cent stamps, a meyer lemon next to two lemon halfs cut open, reading USA in the lower left and 2¢ in the upper right in yellow font

Or you can overpay by $0.30 using three Domestic Forever stamps ($2.04)
USA Forever Stamp, USA flag designUSA Forever Stamp, USA flag designUSA Forever Stamp, USA flag design
4 ounces ($1.98) Two Domestic Forever stamps, one Postcard stamp, one 5¢ stamp, and two 2¢ stamps ($1.98)
USA Forever Stamp, USA flag designUSA Forever Stamp, USA flag designUSA postcard stamp, brown shell with teal backgroundUSA five cent stamps, two bundles of purple grapes with green leaves, reading 5¢ in the upper left and USA in the bottom right, both in purple fontUSA two cent stamps, a meyer lemon next to two lemon halfs cut open, reading USA in the lower left and 2¢ in the upper right in yellow fontUSA two cent stamps, a meyer lemon next to two lemon halfs cut open, reading USA in the lower left and 2¢ in the upper right in yellow font

Or you can overpay by $0.06 using three Domestic Forever stamps ($2.04)
USA Forever Stamp, USA flag designUSA Forever Stamp, USA flag designUSA Forever Stamp, USA flag design
5 ounces ($2.22) Three Domestic Forever stamps, one 10¢ stamp, one 5¢ stamp, one 2¢ stamp, and one 1¢ stamp ($2.22)
USA Forever Stamp, USA flag design