How do you determine USPS piece weight?

Determining the USPS piece weight using the method of placing a sample on the scale and dividing the total weight by the number of pieces is accurate because it allows for an empirical measurement that accounts for any variations in weight across multiple pieces. This approach is particularly useful in bulk mailings where not every piece may weigh exactly the same due to factors such as variations in material or content.

By weighing a sample and calculating the average weight, you ensure that you have a representative figure that reflects the actual mailing. This method can help in establishing accurate postage costs, especially when mailing promotions or large numbers of items where slight differences in weight can significantly impact pricing tiers.

The other methods, while they have their contexts, do not provide the same level of assurance. For example, weighing a single piece and multiplying assumes uniformity, which may not hold true in bulk mail scenarios. Using the average weight from previous mailings could lead to inaccuracies if there have been changes in material or content since then. Calculating based on dimensions may offer a theoretical weight but will not account for variances in density or other factors that affect actual weight.