Peanut butter is generally sold by weight, but many recipes specify peanut butter in units of volume, such as tablespoons or cups. This can be confusing when you wish to purchase enough peanut butter for a specific recipe without ending up with more than you can use. The conversion process is fairly simple, however.
Determine the number of pounds of peanut butter you wish to convert. A container may specify a number of pounds, a number of ounces, or both. Divide the number of ounces by 16. Add this to the number of pounds. For example, if the container specifies 1 pound, 8 ounces, divide 8/16 to get 0.5. Add this to the number of pounds: 1 + 0.5 = 1.5 pounds.
Enter the number of pounds of peanut butter you wish to convert into cups in your calculator. In the example, you enter 1.5 in the calculator.
Multiply this number by 2.25, as there are approximately 2.25 cups of peanut butter per pound. In the example, you have 1.5 x 2.25 = 3.38. So, the container in the example contains about 3.38 cups.