Sizing
What size power station do I need?
Start from your devices — fridge, CPAP, phones — not from watts you don't know. Honest math distinguishes battery-side from AC-delivered capacity, checks startup surge, and models solar recharge reality.
Tools & Calculators
Tools to make the call
Interactive calculators built on the same sourced data behind every BatteryRank score — start from the devices you actually own, and get a real answer against stations we track. No sign-up, no watts you have to look up first.
CPAP
CPAP runtime calculator
Get a runtime answer for your CPAP in under a minute. Set humidifier on or off and your hours per night, and see how many nights each station really lasts — humidification is the setting that changes everything.
Runtime
Fridge runtime calculator
How long will a power station keep your refrigerator cold in an outage? Pick your fridge and days to cover, then see runtime from AC-delivered capacity with compressor surge checked.
Solar
Solar recharge deficit calculator
Will your solar panels keep a station charged, or just slow the drain? Real harvest is far below the panel's nameplate — see the honest daily balance, the recharge deficit, and how many watts you'd truly need.
Cost
Generator vs battery cost calculator
What does it really cost to run a gas generator vs a power station? Compare dollars per kWh delivered — generator, grid-charged, and solar-charged — on live national fuel and electricity prices.
Complete kits: everything the setup needs, not just the station
A calculator tells you which station clears the load. A kit lists the cables, adapters, and backups that decide whether the plan survives contact with a real outage or campsite — each item tied to the scenario that needs it.
- CPAP overnight
- Refrigerator outage
- Weekend camping
- RV starter
- Starlink remote work
- Apartment outage
- Photography + drone
What these calculators can and cannot settle
Six calculators, and they divide into two jobs: three answer "how long will this last", and three answer "is this worth it". Knowing which question you are actually asking is most of the work, because the two produce very different kinds of answer and only one of them is arithmetic.
Start with the sizing tool if you are unsure
It is the only one that takes a whole load list rather than a single appliance, and it is where every scenario page on this site hands off when you want to change something. If you do not yet know whether your question is about one device or several, assume several — the mistake that strands people is sizing for the refrigerator and forgetting everything plugged in beside it.
Every result is a planning estimate, and says so
These calculators apply published efficiency and depth-of-discharge constants to sourced appliance figures. They do not know your battery's age, the temperature of the room, or how hard your particular unit is worked. Treat the output as the optimistic end of a range and leave margin, especially on anything you would be in trouble without.
The cost tools answer a different kind of question
Comparing a battery against a generator, or ranking stations by cost per usable kilowatt-hour-cycle, produces a number that depends on assumptions you supply — fuel price, how often you will actually use it, how long you will keep it. Change those and the answer moves a long way. They are best used to check whether a purchase is in the right order of magnitude, not to pick between two close candidates.
Nothing here needs an email address
Every calculator runs on the page and shows its working, including the constants it used and where they came from. There is no gate, no export, and no result held back in exchange for contact details. If a number here matters to your decision you should be able to check it, which is not possible when the method is hidden.