How Many Stamps Do I Need?

Alex Cook's photo

By Alex Cook

Updated January 2021
Last postage increase January 24, 2021
Covid-19 / Coronavirus status : Delivering normally
Photo of an old envelope reading 'Postage for $country_name'

The United States postal system is an incredible public service. For only $0.55, one can send a letter anywhere in the United States to arrive in 1-3 days! The first $0.55 covers up to 1 ounce. After that, add $0.20 per ounce up to 3.5 ounces.

Jump to: Covid-19 / Coronavirus status,   Envelope requirements,   how to weigh your envelope,   where to buy stamps,   delivery times,   accuracy notes,   where to apply stamps,   postage for more than 3.5 ounces, or   postage for large envelopes (flats)

How many stamps do I need for a letter to the United States?

The number of stamps you'll need depends on the weight. First weigh your envelope using a kitchen scale then add the correct number of stamps, rounding up to the nearest ounce.

Weight Postage
1 ounce ($0.55) One Domestic Forever stamp ($0.55)
USA Forever Stamp, USA flag design
2 ounces ($0.75) One Domestic Forever stamp, and one 20¢ Additional Ounce stamp ($0.75)
USA Forever Stamp, USA flag designUSA additional ounce forever stamp, president heads wearing flag-themed tophats

Or you can overpay by $0.35 using two Domestic Forever stamps ($1.10)
USA Forever Stamp, USA flag designUSA Forever Stamp, USA flag design
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3 ounces ($0.95) One Domestic Forever stamp, one 35¢ Postcard stamp, and one 5¢ stamp ($0.95)
USA Forever Stamp, USA flag designUSA Postcard 35 cent 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 $0.15 using two Domestic Forever stamps ($1.10)
USA Forever Stamp, USA flag designUSA Forever Stamp, USA flag design
3.5 ounces ($1.15) Two Domestic Forever stamps, and one 5¢ stamp ($1.15)
USA Forever Stamp, USA flag designUSA Forever Stamp, USA flag designUSA 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 $0.50 using three Domestic Forever stamps ($1.65)
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

Covid-19 / Coronavirus status: Delivering normally

At this time, mail to the United States is opearting normally. You can track updates on the USPS website. Please note that while first-class mail leters are not experiencing Covid-related delays, other types of mail such as first-class mail packages and Priority Mail are experiencing delays. We monitor for updates daily and will update this page accordingly.

How many stamps for a postcard?

If you're sending a postcard to the United States you'll need one Postcard Stamp for $0.35. You can also overpay using one Forever Stamp for $0.55. 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

Envelope requirements

Your envelope must be a minimum 5” x 3.5”, maximum 11.5” x 6+⅛”, and no thicker than 1/4".

Make sure your envelope is of uniform thickness, rectangular, and bendable. Otherwise, you may have a "non-machinable" envelope and add $0.15 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 $0.21.

How to weigh your envelope

Use a kitchen food scale to measure your envelope’s weight. If you don’t own one, Amazon makes a good entry level scale for $10.99 and there’s a higher end scale from My Weigh for $38 on Amazon Prime. Walmart also offers several cheap kitchen scales like this Milleroo scale for $8.25

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

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.

Accuracy notes

We check postage rate changes weekly.
New prices effective August 29, 2021
Announced May 2021, the latest increase will take effect in August.
  • The cost of a forever stamp will incerase from $0.55 to $0.58
  • Postcards will increase from $0.36 to $0.40
  • Flats will increase from $1.00 to $1.16
  • International forever stamps will increase to $1.30 from $1.20
Previous price increases
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.

Where to apply stamps on a letter

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.

Delivery times for letters to the United States

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

Sending more than 3.5 ounces to the United States or sending large envelopes to the United States

Below are the rates for sending a large envelope ("flat") to the United States. 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 the United States is $1.00. 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 $15.99 ($0.16 each) or 20 pack for $4.83 ($0.24 each). Local office supply stores also have these. Staples offers a 100-pack for $40.79 ($0.41 each).

Note you can't use a bubble envelope as bubble envelopes are typically more than 1/4" thick. Bubble envelopes are usually considered a "package / thick envelope" by the USPS. You can purchase a label on PayPal and print at home or visit your local post office.

How many stamps do I need for a large envelope (flats) to the United States?

The number of stamps you'll need depends on the weight. First weigh your envelope using a kitchen scale then add the correct number of stamps, rounding up to the nearest ounce.

Weight Postage
1 ounce ($1.00) One Domestic Forever stamp, one 35¢ Postcard stamp, and one 10¢ stamp ($1.00)
USA Forever Stamp, USA flag designUSA Postcard 35 cent stamp, brown shell with teal backgroundUSA 10 cent stamp, two red pears reading 10¢ in the upper left and USA in the bottom right, in red font

Or you can overpay by $0.10 using two Domestic Forever stamps ($1.10)
USA Forever Stamp, USA flag designUSA Forever Stamp, USA flag design
2 ounces ($1.20) Two Domestic Forever stamps, and one 10¢ stamp ($1.20)
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 font

Or you can overpay by $0.45 using three Domestic Forever stamps ($1.65)
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 ($1.40) Two Domestic Forever stamps, one 20¢ Additional Ounce stamp, and one 10¢ stamp ($1.40)
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 font

Or you can overpay by $0.25 using three Domestic Forever stamps ($1.65)
USA Forever Stamp, USA flag designUSA Forever Stamp, USA flag designUSA Forever Stamp, USA flag design
4 ounces ($1.60) Two Domestic Forever stamps, one 35¢ Postcard stamp, one 10¢ stamp, and one 5¢ stamp ($1.60)
USA Forever Stamp, USA flag designUSA Forever Stamp, USA flag designUSA Postcard 35 cent stamp, brown shell with teal backgroundUSA 10 cent stamp, two red pears reading 10¢ in the upper left and USA in the bottom right, in red fontUSA 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 $0.05 using three Domestic Forever stamps ($1.65)
USA Forever Stamp, USA flag designUSA Forever Stamp, USA flag designUSA Forever Stamp, USA flag design
5 ounces ($1.80) Three Domestic Forever stamps, one 10¢ stamp, and one 5¢ stamp ($1.80)
USA Forever Stamp, USA flag designUSA 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 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 $0.40 using four Domestic Forever stamps ($2.20)
USA Forever Stamp, USA flag design