Sizing calculator

How much backup power do you need?

Choose your devices, a backup window, and what you are planning for. Advanced electrical controls are optional.

POWER NEEDS

Example planning values — edit them to match your actual devices.

DEVICE 1
Source: Portable Power Match planning methodologyCurated editable planning estimate using a 50% cycling duty cycle. The 300 W startup value is a conservative 3× compressor-start allowance; verify the appliance nameplate.
DEVICE 2
Source: U.S. Department of Energy-hosted plug-load studyRounded planning value based on a measured 57.5 W laptop example; use the charger label or a watt meter for your device.
DEVICE 3
Source: U.S. Department of Energy appliance tableActual draw varies widely with screen size, brightness, and display technology.
DEVICE 4
Source: ENERGY STAR certified light-fixture listingExample certified LED fixture value; edit this to match the wattage printed on each lamp.
DEVICE 5
Source: Apple 20W USB-C Power Adapter specificationsUses a maximum adapter output as a conservative planning value; actual charging draw usually varies over the charge cycle.
DEVICE 7
Source: U.S. Department of Energy appliance tableInput draw can exceed advertised cooking power; verify the appliance nameplate.
LOAD SUMMARY
Devices selected
10
Estimated energy
3,173 Wh
After conversion losses
3,733 Wh
Recommended rated capacity
~4,392 Wh+
Maximum simultaneous load
1,000 W
Startup / surge requirement
543 W

Energy uses each row’s runtime, quantity, and duty cycle. Output sums checked devices; unchecked devices are treated as one-at-a-time loads. Startup replaces that device’s running draw during its start event.

YOUR ESTIMATED NEED
Battery size
~4.4 kWh+
Power output
~1,000 W+
Startup capability
~543 W
See calculation details
Device energy
3,173 Wh
After 85% conversion efficiency
3,733 Wh
After separate 15% reserve
4,392 Wh
RECOMMENDED MATCHES
How scoring works
No product in the current verified set meets the required energy, continuous-output, and surge-output thresholds.