Shipping a Box with USPS

Main Takeaway: For most heavy shipments-including a 40 lb. box-USPS Priority Mail Flat Rate® packaging offers the most predictable, and often the most economical cost. A flat-rate box ships up to 70 lb. anywhere in the U.S. for a single price (e.g., $22.65 retail for a Large Flat Rate Box), avoiding zone-based or per-pound surcharges.…