⏳️ Estimated Time of Arrival (ETA) Calculator

Easily calculate your voyage steaming time and ETA in local time based on your departure and arrival positions, departure time, total distance, and speed. 🎯

Useful?
...

Departure Information

°'
°'

Arrival Information

Enter positive or negative hours to adjust for DST (e.g., 1 or -1)

°'
°'

Auto-detects based on coordinates. You can manually edit this.

Voyage Information

⚙️ How to Use

🧭 Step 1: Enter Departure Details

  • Type the Departure Port name.
  • Input Latitude (degrees, minutes, N/S).
  • Input Longitude (degrees, minutes, E/W).
  • Set the Local Departure Time using the date and time picker.

🗺️ Step 2: Enter Arrival Details

  • Type the Arrival Port name.
  • Input Latitude (degrees, minutes, N/S).
  • Input Longitude (degrees, minutes, E/W).
  • Add Daylight Saving Time (DST) adjustment if applicable.

⚓ Step 3: Enter Voyage Info

  • Enter the Total Distance in nautical miles (NM).
  • Enter the Average Speed in knots.

⏱️ Step 4: Calculate ETA

  • Click “Calculate ETA” to get your Estimated Time of Arrival and steaming time in the destination’s local timezone.

📌 Important Notes

  • Double-check all coordinates and time inputs for accuracy.
  • Apply the correct DST adjustment for the arrival location.

Example:

Departure Port is Map Ta Phut, Thailand (12º 35.0'N, 101º 20.0'E) at 1200 on 23 July 2025, and you're traveling to Weipa, Australia (12º 42.3'S, 141º 40.6'E), a distance of approximately 3,182.8 nautical miles at an average speed of 12.5 knots.

Answer:
Steaming Time: 10 days, 14 hours, 37 minutes
Estimated Time of Arrival (Local at ZD -10)
June 23, 2025, 5:37 AM

Related Maritime Tools

Great Circle Sailing

Shortest path route calculations.

Plane Sailing

Calculations for shorter distances.

Mercator C & D

Standard rhumb line navigation.

Fuel Consumption

Voyage fuel and cost estimation.

DST Calculator

Quick distance, speed, and time conversions.

Complete Guide to Calculating Vessel ETA

Accurately predicting a vessel's Estimated Time of Arrival (ETA) is a critical responsibility for every navigating officer. Port authorities, harbor pilots, terminal operators, and commercial charterers rely heavily on precise ETA updates to coordinate cargo operations and tugboat deployments. Our professional ETA Calculator eliminates the complex manual math involved in timezone changes, allowing you to instantly calculate your arrival time using distance, average speed, and Zone Description (ZD).

Understanding the ETA Calculation Process

Calculating an ETA at sea is significantly more complicated than driving a car across land. Navigators must continuously account for the vessel's speed across the water, the total distance remaining on the passage plan, and the changing global time zones as the ship crosses different longitudes.

  • Steaming Time: First, divide the total distance (in Nautical Miles) by the vessel's average speed (in Knots) to find the total steaming hours.
  • Greenwich Mean Time (GMT): Because local time changes as the ship moves East or West, all professional maritime ETA calculations must first be converted to a neutral baseline, which is GMT (also known as UTC).
  • Zone Description (ZD): The ZD is applied to the GMT arrival time to find the Local Time at the destination port.

The Importance of Zone Description (ZD)

The Earth is divided into 24 standard time zones, each representing roughly 15 degrees of longitude. The Zone Description is the number of hours that must be added to or subtracted from Local Time to obtain GMT. For example, if a port is in Zone -5 (such as New York), you must add 5 hours to local time to find GMT. If a port is in Zone +8 (such as Singapore), you subtract 8 hours from local time to find GMT. Mixing up positive and negative ZD signs is the most common cause of ETA errors on the bridge.

Practical Example: Ocean Voyage ETA

Let's walk through a practical scenario. A container ship departs Los Angeles (ZD +8) bound for Tokyo, Japan (ZD -9). The total passage distance is 4,800 Nautical Miles, and the ship will maintain an average speed of 20 Knots.

  1. Calculate Steaming Time: 4,800 NM ÷ 20 Knots = 240 hours (exactly 10 days of steaming).
  2. Convert Departure to GMT: If the ship departs Los Angeles at 0800 Local Time, the navigator adds the ZD (+8) to find the GMT departure time: 1600 GMT.
  3. Add Steaming Time: 1600 GMT + 10 days = 1600 GMT on the arrival date.
  4. Convert Arrival to Local Time: Apply Tokyo's ZD (-9). To convert GMT to Local, reverse the sign. 1600 GMT + 9 hours = 0100 Local Time the next morning in Tokyo.

By utilizing our dedicated maritime ETA Calculator, Second Officers can instantly generate these updates for daily noon reports without the risk of timezone inversion errors, ensuring the charterer receives flawless information.

Comments

Log in to comment. Go to login

Loading comments...