Boat Speed Calculator

Calculate a boat's average speed from the distance travelled and the time taken. Enter your distance and time to get the speed in km/h.

Formula

Speed = Distance ÷ Time

Average speed is simply distance divided by time.
With distance in km and time in hours, the result is in km/h.
To convert km/h to knots, divide by 1.852 (1 knot = 1.852 km/h).
This gives average speed over the whole trip, not instantaneous speed at any moment.
Keep the units consistent — if you change distance to nautical miles, the answer changes accordingly.

Inputs

Speed = 100 ÷ 2 = 50 km/h, which is about 27 knots.

How is boat speed calculated?

Divide the distance travelled by the time taken. With km and hours, you get speed in km/h.

How do I convert km/h to knots?

Divide km/h by 1.852, since one knot equals 1.852 km/h. So 50 km/h is roughly 27 knots.

Is this average or instantaneous speed?

It is the average speed for the trip. Actual speed will vary with currents, wind, and throttle.

What is a knot?

A knot is one nautical mile per hour, the standard speed unit in marine and aviation navigation.

Can I use other units?

Yes, as long as you keep them consistent. Distance in miles and time in hours gives mph instead of km/h.