Your marine toolbox
Instant calculations for the boat — wind, electrical, navigation, tanks and more. No sign-up. No data sent anywhere.
All marine tools
Wind speed & Beaufort
Convert knots, mph, km/h and m/s. Instant Beaufort scale with sea state description.
Navigation & speed
Knots converter, nautical miles, ETA calculator and hull speed.
Electrical calculators
Voltage drop, cable sizer and battery capacity calculator.
Fluids & tanks
Litres to gallons, tank volume calculator and fuel consumption estimator.
Marine reference
VHF channels, phonetic alphabet, nav lights, sound signals and Mayday procedure.
General converters
Weight, length, temperature and other everyday unit conversions.
What are you trying to do?
Planning a passage
Work out your ETA, fuel needed, hull speed limits and anchor scope for the anchorage.
Wiring / electrical work
Size your cables correctly, check voltage drop and calculate your battery bank requirements.
Tanks & fuel
Calculate tank volumes, convert litres to gallons and estimate fuel burn for a passage.