Overview

Amazon promise extensions are additional time buffers that Amazon automatically adds to your seller-fulfilled delivery promises. These extensions help ensure that the delivery date shown to customers has a higher likelihood of being met, accounting for real-world logistical challenges that can delay shipments. Understanding how promise extensions work is essential for managing your on-time delivery metrics and customer expectations.

Key Points / What Sellers Need to Know

• Promise extensions add extra days to your delivery estimate — Amazon calculates your promised delivery date by combining your handling time, transit time, and any applicable promise extension. The extension provides a buffer that accounts for delays outside your direct control.

• Customers see a different date than you do — When a promise extension is active, the delivery date displayed to shoppers is later than the "ship by" date you see in Seller Central. If no extension is applied, both dates align.

• Extensions are calculated automatically — Amazon determines your promise extension based on your recent delivery performance across all seller-fulfilled, non-Prime orders with a promised delivery date in the past 14 days. The extension is expressed as a number of days and represents an average across those orders.

• On-time delivery is measured against the extended date — Your on-time delivery rate is calculated based on whether items arrive by the Amazon-generated promised delivery date, which includes any promise extension. This means the extended date is the benchmark for your performance metrics.

• Logistical factors drive extensions — Amazon applies promise extensions to account for disruptions such as extreme weather events, transportation network constraints, and other factors that could realistically delay a package in transit.

How Promise Extensions Are Calculated

Amazon uses a rolling 14-day window to determine your promise extension. The system looks at all of your seller-fulfilled, non-Prime orders that had a promised delivery date within the past two weeks and calculates an average extension value expressed in whole days. This means your promise extension is not static — it shifts over time based on your recent fulfillment track record. If your deliveries have been consistently on time, your extension may be minimal or nonexistent. If recent orders have experienced delays, the extension may increase to give future promises more breathing room. Sellers cannot manually set or override this value, as Amazon controls the calculation entirely.