Plan your van. Skip the spreadsheets.
41+ instant calculators for batteries, solar, water, fuel, payload and off-grid living — built for campervan and motorhome owners.
- Calculators
- 41+
- Categories
- 8
- Sign-up
- None
Most used
Popular calculators
Battery capacity
Work out how many Ah of leisure battery you need from your daily appliance load.
Solar panel size
Find the panel wattage needed to break even on a typical day.
Fuel cost
Trip fuel cost from MPG/L per 100km and price per litre.
Payload
Total payload from passengers and gear vs vehicle GVW.
Off-grid duration
Combine battery, water and waste limits to find max days.
Tank size
Find the fresh water tank size for your trip length.
Every tool you need
Browse by category
Tap a category to see every calculator in it.
Battery & Solar
Size your leisure battery, solar panels, inverter, fuses and cables.
Water
Plan tank size, daily usage, refills, grey water and pump flow.
Fuel & Trips
Trip fuel, MPG, cost per mile, route and journey estimates.
Weight & Payload
Stay legal with payload, axle distribution and overweight checks.
Build & Materials
Insulation, plywood, flooring, timber and material costs.
Heating, Gas & Air
Gas usage, diesel heater fuel, heater sizing and ventilation.
Off-Grid Living
Combine power, water and waste to plan how long you can stay out.
Costs & Budget
Whole-build cost, budget tracker, DIY vs pro and breakdowns.
Why VanTools
Built for the road, not the desk.
Instant results
Every tool calculates as you type. No submit buttons, no reloads.
Local units & currency
Switch miles/km, litres/gallons, kg/lb. Currency follows your country.
Works on patchy 3G
Mobile-first, fast and lightweight — usable anywhere you camp.
Ready to plan your build?
Jump straight to the most-used tools — battery sizing, payload checks and trip fuel costs. No account needed.