How do you calculate postage on package sent USPS?

To calculate postage for a package sent via USPS, first weigh the package and measure its dimensions. Then, use the USPS Postage Calculator available on their website, or refer to the rate charts based on the package's weight, size, and destination. Select the desired service (e.g., Priority Mail, First-Class Package) and any additional options like insurance or tracking to find the total cost. Finally, you can purchase postage online or at a USPS location.