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How to use
- Enter Usable energy kWh.
- Enter Load power W.
- Calculate, then review power, price and period before comparing.
How it is calculated
Runtime hours = usable kWh ÷ load kW
Example
Usable energy of 6.912 kWh with a 1,000 W load gives a theoretical runtime of 6.912 hours if the load stays constant.
Important notes
Variable loads, startup surges, inverter limits and temperature can reduce real runtime. Do not treat the result as a guarantee for critical backup.
Worked examples and interpreting results
| Case | Calculation | Result |
|---|---|---|
| Load kW | 1000 ÷ 1000 | 1 |
| Runtime | 6.912 ÷ 1 | 6.912 |
Frequently asked questions
Will a 1,000 W load always stay at 1,000 W?
Not necessarily. Many devices cycle or vary with demand, so use a representative average.
Is the result an actual utility bill?
No. It is a calculation from your usage, price and inputs; real tariffs, taxes and fixed fees may add other items.
How can I improve accuracy?
Use measured or device-specific power and usage plus the actual electricity price for the same period.