USPS medium box shipping cost calculator
Estimate USPS shipping cost impact for a medium box, including label cost, packaging, insurance, and customer charge. Use this to decide whether to charge shipping, build it into the item price, or set a free-shipping threshold.
Shipping decision notes
A cheap label can still lose money if packaging, insurance, refunds, and marketplace fees are ignored. Recalculate when carrier rates change.
Usps Medium Box Shipping Cost Calculator assumptions
Shipping estimates can change because carriers price packages by service, zone, weight, dimensions, surcharges, insurance, delivery speed, and account discounts. Treat the output as a pre-check before buying postage.
For best results, measure the packed item, include packaging weight, compare at least two services, and leave room for supplies, returns, and marketplace fees charged on shipping.
How to use this page well
Use this page as a planning aid, not a final quote or official rule. Replace defaults with your own numbers, compare more than one scenario, and check any important fee, tax, carrier, or marketplace policy against the official source before acting.
- Use real costs instead of rounded guesses whenever possible.
- Review the result together with shipping, returns, discounts, taxes, and payment fees.
- Save or repeat the calculation when costs change, because small inputs can change profit quickly.