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Home Battery Runtime Calculator

Estimate how long a home battery can support a steady electrical load.

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Step 1

Enter your numbers

Instant result · No signup or email required.

Method

How this home battery runtime calculator works

Usable battery energy is rated kWh × usable percentage. Runtime hours equals usable kWh ÷ load kW.

How to use it

  1. Battery capacity. Enter the value in kWh.
  2. Usable capacity. Enter the value in %.
  3. Average load. Enter the value in W.
  4. Request the result. Select “Show my result.” No account or email is required.

What to do with the number

Real loads change minute to minute, and inverter efficiency plus surge loads can reduce runtime. Estimate the average wattage of the circuits you actually plan to back up rather than using whole-home peak demand.

Planning estimate

Use this result as a starting point, not a guarantee. Product specifications, site conditions, manufacturer guidance, local codes, taxes, labor, tolerances, and rounding can change the real requirement or cost.

FAQ

Questions about this calculator

What does the Home Battery Runtime Calculator calculate?

Estimate how long a home battery can support a steady electrical load.

What inputs does this home battery runtime calculator use?

The calculator uses battery capacity, usable capacity, average load. You can replace every default with the numbers that match your situation.

How should I use the Home Battery Runtime Calculator result?

Real loads change minute to minute, and inverter efficiency plus surge loads can reduce runtime.

What can make the real-world result different?

Estimate the average wattage of the circuits you actually plan to back up rather than using whole-home peak demand.

Can I change the calculator assumptions?

Yes. The editable inputs are the assumptions. Replace the default values with your own measurements, prices, rates, quantities, or specifications before requesting the result.

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Next useful step

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