Companies engaged in import and export frequently use terms such as ETD, ETA, ATA, and ATD in both air and ocean freight transportation. These internationally recognized concepts for supply chain management are used for accurate date and time planning. In this article, we will examine the meanings of these terms, why they are important, and the factors that influence these dates.

What is ETA?

ETA, or estimated time of arrival, is a term frequently used worldwide to indicate the time of arrival. Its abbreviation stands for estimated time of arrival. In the shipping and logistics industry, it is used to estimate when a shipment will arrive at its destination port.

An estimated time of arrival (ETA) for a vessel, container, or package in transit can help the buyer track their shipment without having to call the shipping office. Concurrently, operations teams can use this data to optimize delivery schedules and improve predictability.

How is ETA Calculated?

Many factors are taken into account when calculating ETA. These include:

• Distance between the point of origin and destination

• Average speed of the vessel

• Number of ports of call

• Climate and weather conditions

• Time required for refueling

• Port traffic and congestion

• Unforeseen emergencies

Considering the relevant factors, you can calculate the estimated time of arrival with the following formula:

Estimated time of departure + Estimated transit time = Estimated time of arrival (ETA)

When providing ETAs, carriers must accurately estimate the time spent in processes. Here, real-time visibility through API integration and smart technology helps track vessels and provide the precise port arrival time for the vessel or container.

What is ETD?

ETD stands for estimated time of departure. It is the date/time when the vessel or container is expected to depart from its port of origin. ETD is important because it provides information about the vessel's departure and informs buyers about the expected scheduled times for the destination port.

Based on the estimated time of departure (ETD), carriers calculate the expected time of arrival (ETA) and estimated completion/delivery time as part of the shipment flow.

How is ETD Calculated?

The booking confirmation sent by the ocean carrier or freight forwarder typically includes an estimated time of departure. It is calculated by taking several factors into account, such as:

• Vessel schedule

• Maintenance and refueling

• Weather conditions at both the port of origin and various ports along the way

• Port congestion and equipment

• Labor and other factors

These factors affecting ETD are further categorized by some businesses specializing in marine delay insurance. These include:

• Shore-side factors: Conditions such as labor unrest, traffic congestion, infrastructure difficulties, and transportation issues at ports.

• Vessel-related factors: Factors such as weather delays and vessel mechanical breakdowns.

Calculating the estimated time of departure is highly important as it assists buyers with berth planning, tug arrangement, shore clearance, departure schedule planning, and other operations.

What is ATA?

ATA stands for actual time of arrival. It is the exact time when a specific mode of transportation reaches its intended destination. Its abbreviation stands for actual time of arrival.

Unlike estimated time of arrival (ETA), ATA is the time when the plane, train, bus, ship, or other mode of transportation actually arrives, which may be later or earlier than the ETA due to standard delays.

ATA is when a vehicle arrives at a destination, but it can still vary by company or industry. For flights, ATA may be when the aircraft reaches its gate, not when it lands, and for an Uber ride, it may be when the driver arrives at the pickup area.

What is ATD?

ATD stands for actual time of departure. It is the time when an aircraft actually takes off. Its abbreviation stands for actual time of departure. In logistics, ATD can also refer to the point in time when a shipment is sent. Its counterpart is ATA, the concept that describes when the shipment arrives.

While the Estimated Time of Departure (ETD) is a known factor, the Actual Time of Departure can only be specified once the shipment is on its way. Comparing ETD and ATD helps identify a delay in delivery.

Why are the Terms ETA, ETD, ATA and ATD Important in Logistics?

Determining and processing each of these dates accurately makes it possible to manage the supply chain with minimal friction. In particular, each date is of great importance in terms of port management, the smooth progress of transportation, and the timely receipt of products by importing companies.

ETA and ETD, which are the estimated times of arrival and departure, are important for port management. Through these dates, port authorities:

• Allocate resources efficiently.

• Minimize vessel waiting times.

• Keep port congestion under control.

In this way, time is saved by preventing unnecessary truck queues and waiting fees at the ports.

Accurate determination of these dates has a major impact not only on port management but also on the progress of the transportation process. With the rapid growth in world population, the supply of many products has become more critical than usual.

Vessel capacities and the number of voyages have increased. For this reason, the estimated arrival and departure dates, ETA and ETD, have begun to affect the entire process in this sense. A vessel arriving later or earlier than specified can disrupt the entire process by negatively affecting other voyages.

Finally, determining these dates in the most accurate way is also highly important for importing companies. Importing companies plan their product supply according to the ETA information given to them.

Most importing companies act by anticipating extensions in transit times. However, some delays negatively affect the supply time of the product. For example, a product transported with a transshipment service may wait at the transshipment port for one or two weeks depending on the congestion at the port.

This delay can cause heavy penalties or loss of customers for the importing company. It is highly critical for importing companies that the estimated arrivals provided by carrier companies are realistic.

What are the factors that negatively affect ETA and ETD information?

Since these dates are estimates, they can naturally deviate from actual information from time to time due to the effect of some situations. Situations that negatively affect this information can be exemplified as follows:

• Adverse weather conditions

• Strikes

• Congestion at the port of destination

• Congestion at the port of origin

• Vessel breakdowns or accidents

• War or pirate attacks

We recommend reading our relevant blog content for things to consider when exporting via ocean transport and the key points of this shipping method.