About Power Station Sizer
Power Station Sizer is a small independent project offering free calculators for working out roughly what size portable power station or battery a given set of devices needs.
What this site does
The main calculator estimates the battery capacity needed to run a list of devices for a chosen number of days. Companion pages estimate how long a given power station would last, how long solar panels take to recharge one, and what size solar array a recharge deadline calls for. There are also device-specific versions for CPAP machines, refrigerators, and Starlink.
Everything runs in your browser. There is no account, and nothing you enter is sent anywhere.
How the estimates are produced
Each calculator takes the numbers you enter — device wattage, hours of use, backup days, and a few efficiency settings — and applies standard, publicly known power formulas: watts multiplied by hours for energy, division by inverter efficiency for conversion loss, and so on. The full method is written out on the methodology page.
Every result is a planning estimate, not a measurement or a guarantee. Real hardware varies with model, firmware, temperature, battery age, and how it is used.
Independence from brands
This site is not owned by, affiliated with, sponsored by, or endorsed by Jackery, EcoFlow, BLUETTI, or any other power station or battery manufacturer. Brand and product names are trademarks of their respective owners and are used only to describe categories of equipment.
Where the site points to product families, it does so as a starting point for your own comparison — never as a ranked list. See the affiliate disclosure for how outbound links are handled.
Check the real specifications
Before buying anything, confirm a product's actual usable capacity, continuous and surge (starting) output, and maximum charge and solar input in the manufacturer's official documentation. A capacity-class suggestion from this site is only a guide to which size range to shop in.
Who runs it
Power Station Sizer is maintained by an independent enthusiast, not a licensed electrician or professional engineer, and nothing here is professional engineering, electrical, or safety advice. For anything involving home wiring, medical equipment, or a critical backup need, consult a qualified professional. Questions and corrections are welcome through the contact page.
Try the calculator
Head to the main power station size calculator to enter your own devices and settings.