VanSpecs tools
Engineering Calculators
Browser-based tools for planning practical caravan, marine, tiny house and shared off-grid systems.
Complete Off-Grid System Planner
Plan daily loads, battery, solar, charging sources, inverter, MPPT, cable and protection checks in one workflow.
Open calculator →Solar, Battery and Cable Calculator
Estimate RV energy use, battery capacity, solar panel power and DC cable size.
Open calculator →Battery Bank Calculator
Estimate usable battery capacity, autonomy and the number of batteries required.
Open calculator →Cable and Fuse Calculator
Estimate DC cable size, voltage drop, ampacity and fuse class for RV circuits.
Open calculator →Inverter Sizing Calculator
Estimate continuous power, surge rating and battery-side current for an RV inverter.
Open calculator →DC-DC Charger and Alternator Calculator
Estimate alternator reserve, driving charge, cable size and fuse guidance for a DC-DC charger.
Open calculator →Water Tank and Autonomy Calculator
Estimate daily water use, tank autonomy, water payload and grey-water capacity.
Open calculator →Caravan Towing and Payload Calculator
Screen towing ratio, vehicle payload, MTPLM headroom and nose-weight margins.
Open calculator →Diesel Heater Fuel and Runtime Calculator
Estimate heater runtime, daily diesel consumption and 12V electrical demand.
Open calculator →LPG Bottle Runtime Calculator
Estimate LPG runtime and daily gas consumption for caravan appliances.
Open calculator →AC Shore Power and Generator Load Calculator
Estimate AC current, startup load, source VA and breaker margin.
Open calculator →12V Water Pump and Accumulator Calculator
Estimate pump duty, runtime, starts and daily electrical demand.
Open calculator →Caravan Payload and Weight Calculator
Estimate loaded mass, payload, nose weight and axle-group load.
Open calculator →Marine Bilge Pump and Battery Calculator
Estimate derated bilge flow, pump current, emergency battery runtime and water removal.
Open calculator →Tiny House Heat Loss Calculator
Estimate simplified transmission and ventilation heat loss for early HVAC planning.
Open calculator →Rainwater Harvesting Calculator
Estimate roof runoff capture, cistern storage and existing tank autonomy.
Open calculator →