Messages from eBay customers now show an Estimated Delivery Date inside the order screen. The date is calculated based on delivery options already configured in your seller account using the following formula: Date of shipment + range of estimated shipping time = estimated shipping time from date to date.
ebay estimated delivery date
So for example, a product is shipped on June 1st and it has an estimated time of 2-3 days. That means the estimated delivery date is June 3 to July 4.