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How Many Stamps Do I Need?

how many stamps do i need

Are you getting ready to send an important letter or parcel? 

Having to head on over to the post office every time you want to send mail is a real chore. It’s much quicker and easier to simply pop the item in a postbox on the way past. However, you need to make sure you attach the right amount of postage before doing this. Otherwise, the receiver will have to pay the difference, or the mail will be returned to you.

So, let’s find out, how many stamps do I need?’

Working Out the Number of Stamps

Several factors determine the amount of postage you need. It is important to take all these factors into account when calculating postage. Failing to do this correctly means that your mail might not reach its destination.

Standard-sized letters

The size of the letter matters when it comes to working out the postage. The price for standard-sized letters is calculated to make it easy to know how much postage to use. However, you need to have a good understanding of what a standard-sized letter is.

Standard-sized letters have to be:

  • Rectangular.
  • At least 3½ inches high by 0.007 inches thick by 5 inches long.
  • Less than 6⅛ inches high by ¼ inch thick by 11½ inches long.
  • Uniform in thickness without any bulges or bumps.
  • Bendable or flexible.
  • Sealed in a paper envelope.

Forever Stamps 

One of the things that make calculating postage tricking is that rates change fairly often. Fortunately, using Forever Stamps easily solves this issue. You can always use a single Forever Stamp to cover the cost of sending a standard-sized letter First-Class.

No matter when you purchased the postage, it can always be attached to a letter weighing one ounce or less. This allows you to purchase the postage in bulk to keep it close to hand when you need it. This can save a trip to the post office if you send standard-sized letters fairly regularly.

Square cards 

If you want to send a square greeting card through the mail, it won’t meet the regular First-Class requirements. The shape of this card means that it can’t be sorted by the machines used by USPS. Therefore, these cards have to be sorted by hand, and the postage has to be calculated manually.

Because extra steps are involved, the postage is slightly higher. The United States Postal Service charges an additional fee of $0.17 for this service. This is added to the standard First-Class postage.

Non-machinable stamps

Letters and cards that cannot be sorted by machine are classified as non-machinable. For this type of mail, it is best to cover the regular postage fee as well as the extra postage with a non-machinable stamp.

Other mail that requires a non-machinable stamp includes:

  • Envelopes that contain irregularly-shaped objects like keys and coins.
  • Items enclosed in plastic material.
  • Envelopes featuring metal, string, or button closures.

International Mail

The above postage rates cover mail that is sent within the United States. Even when sending mail to another state, the postage rate will be the same as to the next town. However, there are different postal fees to pay when sending mail to other countries. 

International Mail


The standard fee for sending a First-Class letter to Canada is $1.30. This fee covers letters that weigh up to two ounces. To cover the postage, simply attach one Global Forever Stamp to the letter. These are usually circular and feature the word Global printed on the edge.

Global Forever Stamps always keep their value and can always be used to cover the postage. For heavier letters, you need to attach a little extra postage. 


The usual fee for sending a First-Class letter weighing up to one ounce to Mexico is also $1.30. If the letter weighs between 1.1 and two ounces, the fee is $1.96. 


Sending a one-ounce letter to Australia will set you back $1.30. If your letter weighs between one and two ounces, the postal fee is $2.25. 


If you want to send a one-ounce letter to England, you simply need one Global Forever Stamp. For heavier letters, you will generally be charged $2.43.

The Number of Stamps Per Weight

Aside from the type of mail and the distance covered, the weight also has an impact on the number of stamps needed. It stands to reason that the heavier the mail is, the more stamps you will need to attach. Here’s a breakdown of the amount of postage required for different weights. 

The Number of Stamps Per Weight

One ounce 

You need to affix one Forever stamp to mail that weighs up to one ounce. You also need to make sure that the mail conforms to the set dimensions when using this postage. 

1.5 ounces

The pricing is less flexible for mail weighing more than one ounce. To find the correct fee, you need to calculate the weight to the next ounce. This means that the mail weighing between 1.1 and 1.9 ounces is charged at two ounces. Fortunately, the fee for the additional ounce is only $0.20. if your mail weighs 1.5 ounces, you need to affix $0.78 in postage. 

The ways of affixing the correct postage are:

  • One Forever stamp plus one-ounce stamp.
  • A Forever stamp plus two ten-cent stamps.
  • One Forever stamp, a ten-cent stamp, and two five-cent stamps.

Two ounces

The cost for mail weighing exactly two ounces is $0.78. The three methods outlined above can be used to cover the postage. However, there is an extra fee if the mail weighs 2.1 ounces or over. 

Three ounces

The postage rate is $0.98 for letters that weigh between 2.1 and three ounces. The ways of affixing the correct postage are:

  • One Forever stamp plus two-ounce stamps.
  • One Forever stamp plus one-ounce stamp and two ten-cent stamps.

Four ounces

Letters weighing 3.5 ounces and over fall into the large envelope mailing class. Because these envelopes are bulkier and heavier, they require more postage. The current charge for these types of letters is $1.76.  

The ways of affixing the correct postage are:

  • Three Forever stamps plus a two-cent stamp.
  • Two Forever stamps plus three ounce-stamps.
  • Two Forever stamps plus two ten-cent stamps and two-ounce stamps.

Over four ounces

Working out the exact postage for mail weighing more than four ounces can be tricky. Therefore, it is best to take a trip to your local post office branch. A member of staff will weigh your mail and affix the correct postage for you. 

Working Out the Number of Stamps at Home

By now, you should have a good idea of how many stamps to attach to your letters and parcels. However, there may be times when you need a little extra help. Here are some ways to work out the postage from the comfort of your own home.

Choose Forever Stamps

In many cases, you only need to attach one or two Forever Stamps to your mail. There is no penalty for attaching a little more postage than you actually need. Therefore, attaching two or even three Forever Stamps to your mail is a safe bet. 

Choose Forever Stamps

Measure your mail

If your letter or package is larger than the standard size, it’s a good idea to measure it. You can use a measuring tape or ruler to find the width and length. For bulkier envelopes and parcels, you need to add the thickness to the width and length. This will make it easier to determine the overall size and calculate the postage.

The measurements should be as precise as possible. However, you can round up or down slightly to make sure the postage is correct. If your parcel is particularly large, you will usually need to take it to a post office branch. 

Weigh your mail

If you are adding items like gifts or photos to your envelope, it’s best to weigh it. You need to use a weighing scale that displays the weight in grams or ounces. For small parcels and envelopes, a kitchen scale should be fine. You can use a digital bathroom scale to measure a larger and heavier parcel.

In most cases, you will need to round up the weight of your mail to the next ounce. If you don’t have access to a weighing scale, it’s best to visit the post office. You can then get your mail quickly weighed and can work out the accurate fee. 

Consider the mail class

There are slightly different fees for the three standard mail classes. When working out the postage, you need to choose Ground, Priority, or First-Class mail. To choose the right class, consider when you need it to arrive as well as the overall weight.

Ground mail

This is also referred to as standard shipping and usually takes two to eight business days. This service is best for sending a large quantity of mail at the same time. It can also be used for oversized packages and saves you money on non-urgent mail.

Priority Mail

If you choose this class, delivery is guaranteed between one and three days. Choosing a flat rate box or envelope makes the postage more affordable and easier to calculate. These envelopes and boxes come with a single price for mail weighing up to seventy pounds. 

First-Class mail 

This class typically reaches its destination in between one and three days. However, the weight limit for First-Class mail is thirteen hours. You will need additional postage if you send heavier mail. 

Use a postage calculator 

You can use the postage calculator on the USPS website to receive an accurate result. Make sure you enter all the details as accurately as possible.

The information you need to input includes:

  • Size
  • Weight
  • Class
  • Destination
  • The destination ZIP code
  • Your ZIP code
  • The time and date of shipment

Make the right calculation

To calculate the rate correctly, you need to divide the postage rate by the cost of a Forever stamp. This will quickly show you how many stamps you need to attach to your mail. In most cases, you will only need one or two. For large and heavy envelopes and packages, you may need to attach up to four. 

Attach the stamps

Make sure they are clearly visible, ideally in the upper right-hand corner. If you need to attach multiple stamps, you should arrange them in one or two rows. Make sure they are easy to read and don’t overlap. This will make it easy for the carrier to read the total value and calculate the postage after processing. 

Attach the stamps

Visit the post office

If your mail needs more than one stamp, it’s best to take it to your local post office branch. Certain types of mail can’t be sent through a residential mailbox. This includes mail weighing more than thirteen ounces, large packages, and overstuffed envelopes.

When you get to the post office, you can give your mail to an employee to process it for you. An employee will help you calculate the postal rate and check that the mail is sealed correctly. You can also take advantage of other services, such as printing shipping labels. 

How to Calculate Postage at the Post Office?

Paying a visit to your local post office branch makes it easier to work out the postage. Each branch comes with weighing machines that are very accurate. All you need to do is address and seal your envelope or parcel and take it with you. 

How to Calculate Postage at the Post Office

Get your mail weighed

Ask a post office employee to weigh your mail for you. It will be placed on a digital scale, and you will be told the postal rate immediately.

To calculate the postal rate correctly, the employee may ask for certain information. This may include your ZIP code, the destination, and the mail class you want to use. While certain classes will get your mail to the receiver faster, they come with a higher postal rate. 

Attach the stamps

Once you have chosen the class and agreed to the postal rate, the employee will take care of the rest. Simply hand over your mail, and they will attach the postage for you. However, attaching your own stamps if you have them with you will be slightly cheaper. 

Ask for assistance

Not everyone is a wiz at math, and you might have trouble doing the calculation. Fortunately, a postal employee will be happy to help you. This takes the uncertainty out of attaching the right amount of postage. 

The Penalty for Not Enough Postage

Not attaching enough stamps to letters and parcels means the recipient can be charged an additional fee. This could be a major issue if the recipient doesn’t have the money to hand. When sending mail to a business client, asking them to pay the extra could lose you a client.

In other cases, your mail may be sent back to you. You will then need to attach extra postage before the mail can be resent. This will result in extra time and trouble in the long run.

The Dead Letters Office

The third scenario is that your mail could end up in the dead letters office. This happens when the recipient is unwilling or unable to pay the extra postage and there is no return address. If this happens, your mail will effectively be lost, and your effort will have been wasted.

So, Where Can I Buy My Stamps?

If you don’t have a post office near you, not to worry! We’ve got a few alternatives options for you to look at, such as Does Walgreens Sell StampsDoes Walmart Sell Stamps, and Does CVS Sell Stamps, along with Does Publix Sell StampsDoes Kroger Sell Stamps – The Cost, and Does Target Sell Stamps, or perhaps you’ve already bought your stamps and would like to know Do USPS Stamps Expire?

Whether you’re sending your mail via UPS or USPS, we’ve got you covered! Let’s start with How Fast Is UPS 2nd Day AirWhat Does In Transit Mean At UPS, and Does UPS Notarize official documents, followed by Does UPS Deliver On A Sunday in 2023?

Next, depending on what you’re sending, check out Can I Use Poly Mailers For USPS, as well as Where Can I Drop off USPS PackagesHow Much Is A PO Box At USPS, and Does USPS Forward IRS And Other Government Mail if you’ve moved to a new address and awaiting your passport.

Final Thoughts

Working out how many stamps you need is fairly simple when you know how. The weight, size, shape, and dimensions of the mail all need to be taken into consideration. Failing to factor in one of these elements means that the postage could be incorrect.

Finding the information you need to calculate the postage can be done easily. This allows you to purchase Forever Stamps in advance and skip a trip to the post office. However, USPS employees are always available to help you if you need assistance.

Happy Posting!

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