How to Estimate the Weight of Letter-Size Paper for Mailing

You can estimate the weight of letter-size paper for mailing.

When getting ready to mail something, you may not know how much postage to use. If you don’t have a mail scale at home, however, you can still calculate the weight of the letter-size paper using some simple math. Keep in mind that in many cases, there are other criteria that affect the cost of the postage.

  • Package of paper
  • Calculator (recommended)

1 Why Letter Paper Weight Is Important

You may be wondering how the weight of your letter-size paper affects its postage price. According to the United States Postal Service, the heavier the mail, the higher the postage. However, weight isn’t the only thing that you need to consider when calculating the postage price. The type of mail you’re sending will also affect the cost.

Here are some common options from the USPS:

  • Priority Mail Express​: The weight and distance of travel are what is used to calculate the price. In some cases, you can also choose flat-rate packaging. You may be able to save on postage depending on the type of account you have, such as a USPS Corporate Account.
  • First-Class Mail:​ With this kind of mail, only the weight of the mail and the shape of the parcel determine the postage price.
  • Priority Mail:​ Weight, size and distance affect the postage price for this type of mail. You can also select flat-rate packaging which means you pay the same price no matter the weight of your mail, up to 70 pounds.
  • USPS Marketing Mail:​ Instead of pricing by the exact weight, this kind of mail is priced by the sort level. These can include Carrier Route mail, Automation mail and Machinable Nonautomation mail, among others.
  • USPS Retail Ground, Parcel Select and Bound Printed Matter:​ For these types of mail, you need to consider the weight as well as the distance the mail needs to travel to determine the postage.
  • Library Mail and Media Mail:​ These types of mail only factor in the weight to determine the postage, not distance or any other criteria.

2 How to Estimate Your Letter Paper Weight

The USPS recommends using a scale to weigh your letter. However, the scale you have at home may not be sensitive enough to register the weight of a few sheets of paper. Keep in mind that the USPS actually rounds the weight of the package up, according to their instructions on calculating postage. This means that if your letter weighs 0.5 ounces, then the USPS will round it up to one ounce.

If you have the packaging for your paper, take a look to see whether it states the weight of the paper. For example, a package of 500 sheets of letter-size paper will say it is 20 pounds. However, this isn’t the actual weight of the package. In fact, the package of 500 sheets of paper actually weighs five pounds (this is because the 20-pound weight is actually calculated using reams of paper, which are four times the size of a letter-size paper, according to Lewan Technology). To calculate the letter-size paper’s weight, you will need to divide 20 pounds by 2,000 sheets of paper, which gives you 0.01.

You will then need to multiple 0.01 by 16, which is how many ounces there are in a pound. The result is 0.16 ounces per piece of letter-size paper. Using this number, you can calculate the weight of your total letter paper weight. For example, if you have three pieces of paper, just multiply 0.16 by three.

3 Other Elements to Consider in Your Postage Price

Keep in mind that you will also need to consider elements other than letter paper weight to get the correct postage price. These include:

  • The classification of mail you’re sending (such as Priority Mail or Marketing Mail)
  • The dimensions of the letter
  • The distance the letter is traveling

You can use the USPS postage calculator to determine the exact postage price.

  • Use the link in the Resources section to see a weight conversion chart for other common types of paper.

Anam Ahmed is a freelance writer and editor based in Toronto, Canada. She writes on everything from business to parenting, travel to technology. Learn more at