Free off-grid power calculators
How Much Off-Grid Power Do You Actually Need?
Choose what you want to run and we'll calculate the battery capacity, inverter output and solar setup you need — before you spend a cent on equipment.
Start with what you want to power
Estimated daily use
1.12 kWh
| Appliance | Watts | Hours/day | Qty | Wh/day | |
|---|---|---|---|---|---|
| 12V camping fridge (small, ~20–40L)DC (12V) | 1,080 Wh | ||||
| Smartphone chargingDC (12V) | 20 Wh | ||||
| LED camp light / lanternDC (12V) | 20 Wh |
Appliance library
Wattages shown are estimates. Check the rating label or manual of your actual appliance for the most accurate value — every field is editable once added.
Continues in the full Power Planner with these appliances already added — no account needed.
Flagship tool
The Off-Grid Power Planner
Build your entire electrical setup step by step — use case, trip length, appliances and assumptions — and get a full battery, inverter and solar recommendation, then see matching products.
Popular Calculators
Power Station Size Calculator
Work out what size portable power station you need in Wh, based on the devices you want to run, how many hours per day, and how many days off-grid.
Camping Power Calculator
Calculate your camping power needs — fridge, lights, phones, Starlink and more — and get a recommended power station and solar size for your next trip.
Caravan Power Calculator
Size your caravan's 12V and AC appliance load, battery bank, solar array and inverter for extended off-grid touring.
Battery Runtime Calculator
Estimate how long a battery or power station will run a given load, based on capacity, chemistry, usable depth of discharge and efficiency.
12V Fridge Runtime Calculator
Estimate how long your 12V camping or caravan fridge will run on a given battery or power station, using measured or estimated daily consumption.
Solar Panel Size Calculator
Calculate the solar array size you need based on daily energy consumption, peak sun hours and system efficiency.
Inverter Size Calculator
Calculate the continuous and surge inverter capacity you need based on the AC appliances you plan to run, including simultaneous use.
How It Works
Add Your Appliances
Tell us what you want to power and how often you use it.
Calculate Your Requirements
We'll estimate battery capacity, output and solar requirements.
Compare Matching Equipment
See products whose published specifications match your calculated setup.
Plan Power For Your Setup
Camping
Fridge, lights, phones, Starlink and more for weekend to multi-day trips.
Caravan
Battery bank, solar and inverter sizing for extended touring.
RV
Boondocking power planning in familiar North American terms.
4WD / Overlanding
Build a custom setup for remote, self-sufficient travel.
Off-Grid Cabin
Size a larger battery bank and solar array for a fixed off-grid base.
Emergency Backup
Work out what capacity keeps essentials running when the grid goes down.
Calculations you can actually see
Every calculator shows its working — watts × hours × quantity, reserve percentage, inverter efficiency and solar assumptions — instead of a black-box number. Read the full methodology, including its limitations, on How We Calculate.
Product matches, not guesses
Once you know your requirement, we match it against published product specifications — capacity, output, solar input, weight, price and expandability — using a transparent scoring system. Higher commission never means a higher rank. See How We Review Products and our affiliate disclosure.
Guides
In-depth guides on sizing, LiFePO4, solar and more are being published progressively — we'd rather ship fewer, genuinely useful guides than a wall of thin content.
Browse Guides →Frequently Asked Questions
What size power station do I need?+
It depends on what you're running and for how long. Use the Power Planner or Power Station Size Calculator to add your actual appliances and get a specific Wh recommendation, rather than relying on a generic rule of thumb.
How is this site different from a 'best power stations' article?+
We calculate your requirement first — capacity, continuous output and solar input — based on what you're actually running. Product matches are shown only after that calculation, ranked against your requirement using transparent, published specifications, not commission rates.
Is this free to use?+
Yes — every calculator on this site is free, with no account or sign-up required.
Do you test the products you recommend?+
Product entries are built from official manufacturer specifications and, where available, verified third-party sources — not hands-on lab testing. See How We Review for full detail on our methodology.