EDD is the estimated date when the customer is expected to receive the order. We calculate this date based on how long it takes to dispatch the item (handling time), and how long it remains in transit.
It is important to enter accurate estimates for handling and transit times to help manage customer expectations.
Handling time or the lead time-to-dispatch is the time between when the customer places the order, and when you give it to the delivery service. There are two ways to provide this estimate.
Transit time is the time between when the delivery service gets the order and when the customer receives it. This is calculated based on the carriers (Royal Mail, DHL and so on) and the delivery rates you choose.
The actual delivery date is when the customer receives the order. The carrier will notify Amazon about the actual delivery date only if you provide a valid tracking number while confirming the order.