Free calculators for planning overland trips and builds. Each one runs in your browser, so there is nothing to install and no sign-up. They give you a solid first estimate; always check the final numbers against your vehicle and the manufacturer’s specs.
Power and electrics
12V Power & Battery Calculator: add your fridge, lights, heater and other devices to see how big your house battery should be, how much solar keeps up with it and what size DC-DC charger fits your driving. Works for lithium and AGM.
More tools for tyres, fuel range and trip planning are on the way.