Plan a sea route and estimate its ETA

PortReckon is a free online tool for maritime route planning. Pick an origin and a destination seaport, and it draws the sea route between them on an interactive map and estimates how long the voyage takes. It is built for freight forwarders, shippers, logistics students, ship spotters, and anyone who wants a quick, visual sense of how far apart two ports are by sea and roughly how long a vessel needs to travel between them.

Everything runs in your browser. There is no sign-up, no vessel-tracking subscription, and nothing to install - open the page and search two ports, and the route is drawn for you. The distance is shown in both nautical miles and kilometres, and the estimated time of arrival is derived from the speed and delay factors you choose.

How it works

1. Search two ports. Start typing a city or UN/LOCODE in the origin and destination boxes and pick from the matches. The dataset covers 14269 seaports worldwide, so most commercial ports are included. As soon as both ports are set, the route is calculated and drawn on the map automatically.
2. Add an optional waypoint. Need the route to pass through a specific point - a transhipment hub or a particular strait? Add a waypoint and the route is drawn origin → waypoint → destination.
3. Set the speed and delays. Enter a vessel speed in knots (a live km/h conversion is shown), optionally apply a slowdown percentage, fixed delay hours, or the weather / congestion / canal presets. The ETA updates as you type, and changing a passage restriction redraws the route itself.

What you can adjust

• Vessel speed. The default planning speed is 16 knots; change it to match the vessel or service you are modelling. Distance stays the same, but a slower speed means a longer ETA.
• Slowdown and fixed delay. Trim the effective speed by a percentage for currents or heavy weather, and add a flat number of hours for port handling, pilotage, or waiting time.
• Delay presets. One-click factors for Weather Impact (+7%), Port Congestion (+5%), and Canal Delay (+4%) so you can stress-test a schedule quickly.
• Passage restrictions. Close the Suez Canal, Panama Canal, or Strait of Hormuz and recalculate to see how a chokepoint disruption reroutes the voyage and how much distance and time it adds.

Reading your results

The distance is reported in nautical miles (nmi) - the standard unit at sea, where one nautical mile is 1.852 km - and in kilometres for reference. The ETA is the sea distance divided by your effective speed, plus any fixed delay you added, expressed as a transit time. Because a ship cannot travel in a straight line across land, the sea distance is almost always longer than the great-circle distance between the same two ports.

Curious why? Our major sea routes guide explains the canals and straits that shape world shipping, and how ETA works breaks the calculation down step by step.

Accuracy and limitations

PortReckon is a planning and visualisation tool, not a navigation system. Routes follow common shipping lanes and fall back to a straight-line estimate when no lane is found; the ETA is a planning figure, not a guarantee of arrival. Real voyages are affected by weather, currents, traffic, port schedules, and routing decisions that this tool does not model. Routes are for planning/visualization only and are not certified for navigation.

This website is provided "as is", for general information and planning only, with no warranty of accuracy, completeness, or fitness for any purpose. To the fullest extent permitted by law, the operators of this website accept no responsibility or liability for any loss, damage, cost, or decision arising from use of the site or reliance on its routes, distances, or ETA estimates. Use at your own risk.

Learn more

New to the terminology? The glossary defines terms like nautical mile, knot, and dead reckoning. Common questions are answered in the FAQ, and the about page covers the data sources behind the map.