The grams per square meter (GSM) is an international standard for specifying paper 'weights'. For more information about what this means open the details panel. The calculator below, is a handy tool, which helps determine the weight of an unknown sample of paper. Weigh a number of sheets of paper and enter the results below to calculate.

Use 10 or more sheets for more accurate results. Weight can be either pounds, ounces, grams or a combination (like pounds and ounces). It adds them, so if you only want ounces or grams, make sure the other fields are empty (or zero value).

Paper size is inches - Letter size is 8.5 wide by 11 long, for example. Enter sheet size of your sample. Press the Calculate button, to see the GSM of your sample, and example weights for typical paper stocks.

Paper weight specifications can be confusing. 80 pound can mean different things depending on if it's Text/offset type paper or cover. These came from how the paper was cut into the base sheet size at the mill (known as basis size). It is the weight (in pounds) of a 500 sheet (ream) of paper cut in the basis size. For example, bond paper, like is typically used in copiers or stationery has a basis size of 17 inches by 22 inches. 500 sheets of 20 pound bond will weigh 20 pounds, and 500 sheets of 24 pound stationery (17x22 size) will weigh 24 pounds. But take the same 24 pound paper in Letter size (which is 1/4 of a basis sheet) and it weighs 6 pounds.

Each paper type has a different size for basis. So if you have text/offset 60 pound is about the same weight as 24 pound bond. Cover-weight stock at 65 pounds is heavier than Vellum Bristol at 67 pounds, and many office supply stores sell 110 pound cardstock, which is really Index. This is actually equivalent to 74 pound Cover weight.

To alleviate confusion, the paper industry along with International Standards Organization (ISO) has adopted gram per square meter (abbreviated gsm or g/m²) paper density to compare different papers. Taking 1 sheet of paper with an area of 1 square meter (approx 39 inches by 39 inches) and find the weight (in grams).

With 20 pound bond, the ISO equivalent is 75 GSM. 80 pound cover weight is 216 GSM. Almost all paper packaging will list the gsm or g/m² next to the traditional paper weight.