Navigation Distance/Time Calculator 🧭
Calculate travel time and ETA for your boat trip. Enter speed in knots and distance in nautical miles to get arrival time.
How to Use the Navigation Calculator
Enter speed (knots) and distance (nautical miles) to calculate travel time and ETA. 1 knot = 1.852 km/h, 1 nautical mile = 1.852 km.
Actual travel time may vary due to currents, wind, and sea conditions. Always plan with extra time.
Enter departure time to automatically calculate ETA. Take extra care when planning night passages.
FAQ
How do I convert knots to km/h or mph?
1 knot = 1.852 km/h = 1.151 mph. A boat traveling at 20 knots is going 37 km/h or 23 mph. 1 nautical mile = 1.852 km = 1.151 statute miles.
How do I calculate ETA for a boat trip?
Travel time (hours) = Distance (nautical miles) / Speed (knots). Add departure time to get ETA. For example: 60 nautical miles at 15 knots = 4 hours. Departing at 08:00 means ETA 12:00. Always add buffer time for currents and sea conditions.
How do currents affect navigation calculations?
Currents can significantly affect actual speed over ground. A 2-knot favorable current adds 2 knots to your speed; a 2-knot adverse current subtracts 2 knots. Check tide tables and current charts before departure and adjust your ETA accordingly.
What is the difference between speed over ground and speed through water?
Speed through water (STW) is measured by your boat's speedometer. Speed over ground (SOG) is your actual speed relative to the seabed, accounting for currents. GPS shows SOG. For navigation planning, use SOG for accurate ETAs.
How do I plan a safe night passage?
Plan night passages carefully: check weather forecasts, ensure all navigation lights work, brief crew on watch schedules, identify hazards along the route, and file a float plan with someone ashore. Reduce speed in reduced visibility and maintain a proper lookout.