How do I know how many stamps to use?

Determining the correct number of stamps to place on an envelope or package can be confusing. The price of postage often changes, and different types of mail require different numbers of stamps. However, with a bit of knowledge about current postage rates and weighings, you can easily figure out how many stamps your mail needs.

What are the current USPS stamp prices?

The current price of a First Class Mail Forever stamp for standard envelopes up to 1 ounce is 60 cents. Each additional ounce costs 21 cents. So if your envelope weighs 2 ounces, you would need 1 First Class stamp (60 cents) plus 1 additional ounce stamp (21 cents) for a total of 81 cents postage.

Here are the current prices for other common USPS mail classes:

Mail Type Price
Postcard Stamp 40 cents
Metered Mail 1 oz letter 57 cents
Large Envelope (1 oz) $1.00
Package (1 lb) $4.00

So for a standard business envelope, you would need a Forever stamp. For a large envelope under 1 ounce, use a Forever stamp plus a 20 cent stamp. And for heavier large envelopes, figure 1 stamp per ounce.

How do I weigh my mail to determine needed postage?

To find out exactly how much postage you need, you’ll need to weigh your envelope or package. Here are some options for weighing mail:

  • Use a small digital kitchen scale. Place the envelope or package on the scale to get the weight in ounces.
  • Take your mail to the post office and use the self-service kiosk scales. These are easy to use and free.
  • Check if your office has a digital mail scale you can borrow.
  • Use the USPS Price Calculator tool online to enter package dimensions and get the postage price.

Once you know the exact weight, you can determine the number of stamps needed based on the postal prices above.

What about extra services like certified mail?

If you are using extra services like certified mail or registered mail, additional postage is required. Here are some common extra service fees:

  • Certified Mail – $3.75
  • Registered Mail – $13.75
  • Return Receipt – $2.91
  • Insurance over $50 – 85 cents

To calculate the total postage cost, you will need to add the weight-based rate plus any fees for extra services. For example, a 2 ounce certified letter would require $1.21 postage plus the $3.75 certified mail fee for a total of $4.96.

International Mail Has Different Stamp Requirements

If you are sending mail to another country, the number of stamps needed will vary based on the destination. USPS provides this handy price calculator tool for international postage:
USPS International Price Calculator.

The starting point is $1.40 for a 1 ounce letter to Canada or Mexico. Other countries range from $1.40 up to $1.80 for the first ounce. Each additional ounce adds between $0.25 to $0.60 depending on the destination.

Packages and large envelopes have tiered pricing by weight brackets. For example, the first pound to Canada is $25.50, while the first pound to China would cost $41.50.

Factors that affect international postage rates

  • Destination country
  • Weight
  • Mail type – letter, large envelope, or package
  • Extra services added

Use the USPS calculator to get accurate pricing. Many countries also have maximum dimensions for envelopes and boxes, so be sure to check the size limits.

What happens if I put the wrong amount of postage?

If you put too little postage on mail, one of two things might happen:

  1. The Postal Service returns the mail to you with postage due.
  2. The recipient has to pay extra postage when they receive it.

To avoid delays and surcharges, it’s always best to weigh your items and add enough stamps. If you do happen to underpay by a small amount, the USPS may deliver it anyway without extra fees.

If you put too much postage on an item, it will still be delivered as usual. However, there is no way to get a refund on unused postage, so be sure to calculate carefully to avoid waste.

Save Money on Postage with Postal Presorts

Businesses that send high volumes of mail can save money by presorting and preparing mailings to qualify for postal discounts. First Class Mail presorted can receive up to $0.07 per piece in discounts.

Some key ways that presorting saves money include:

  • Presorting by zip code to qualify for automation rates
  • Barcoding each piece
  • Shipping mail sorted to destination entry points

Third party mail presort companies are experts at maximizing postal discounts, so consider outsourcing if you have large mailings.

Purchase Stamps in Advance for Added Convenience

Rather than waiting until you need to mail something to buy stamps, consider keeping a supply on hand. Stamp books and coils can be purchased at many grocery stores, pharmacies, office supply stores, and other retailers besides just the Post Office. You can also order stamps online from or sites like

Some other stamp buying tips:

  • Buy Forever Stamps which always stay valid even if rates increase
  • Restock when you’re down to 10-20 stamps
  • Request free USPS Stamp Samples to try out new designs

Having a stash of stamps readily available makes the process of sending mail much smoother. You’ll always know the exact amount of postage needed.

Use USPS Tools to Find Answers about Stamps

The United States Postal Service offers many helpful tools and resources to determine how much postage you need, buy the right stamps, and save money on mailing:

  • USPS Postage Price Calculator – Online calculator provides exact postage rates by destination, weight, and services.
  • USPS Postage Stamps Quick Tool – Convenient site shows current prices and how to buy.
  • Virtual Post Office – Experience the Post Office online with tools to buy stamps and calculate shipping.
  • Mobile app – Download the free USPS app to quickly access postage calculators and other mailing information.
  • Zip Code Lookup – Find zip codes fast to get accurate shipping rates.
  • Post Office Locator – Find local Post Office locations to buy stamps and weigh packages.

So whether mailing a simple letter across town or an international package, the USPS website has all the details on current postage rates and stamp prices to guide you. Bookmark their tools and use them to easily determine how many stamps your mail needs.


Figuring out the correct postage can seem complicated, but just remember these key steps:

  1. Weigh the mail piece to get the ounces
  2. Check current USPS prices for that type and weight of mail
  3. Add extra fees if using special services like certified mail
  4. Purchase enough stamps to match the total price

Use USPS online calculators whenever you are uncertain. Having a scale and plenty of stamps on hand makes the process easier. Apply presort discounts for large business mailings. Following these simple tips will ensure you always use the right number of stamps!

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