eShipRate is an advanced shipping calculator app designed to provide precise shipping rate calculations during the checkout process, ensuring accurate charges based on item dimensions, weights, and a wide range of parameters. It offers features like multi-box shipments, flat-rate options, and real-time rates from virtually any shipping carrier worldwide, enhancing the ecommerce experience. The app includes free shipping options, origin-specific rates, and delivery date estimates, providing flexibility tailored to customer and business needs. eShipRate also offers intelligent packaging solutions, determining whether items will fit in a box for efficient use of flat-rate services like FedEx OneRate and UPS SimpleRate. It supports origin-based shipping for each item, with plans to expand to multiple origins for the same item. With the app's ability to split orders into multiple shipments and limit certain items, like lithium batteries, per box, eShipRate optimizes shipping for cost savings and safety compliance.